DRI TM Tricyclics Serum Tox Assay
Device Facts
| Record ID | K213875 |
|---|---|
| Device Name | DRI TM Tricyclics Serum Tox Assay |
| Applicant | Microgenics Corporation |
| Product Code | LFH · Clinical Toxicology |
| Decision Date | Dec 21, 2022 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 862.3910 |
| Device Class | Class 2 |
Indications for Use
The DRI™ Tricyclics Serum Tox Assay is a homogenous enzyme immunoassay intended for the qualitative and/or semiquantitative determination of the presence of tricyclic antidepressants (TCAs) in human serum, plasma, or urine of patients at a cutoff concentration of 300 ng/mL in patients suspected of drug overdose. The semi-quantitative mode is for the purpose of enabling laboratories to determine an appropriate dilution of the specimen for confirmation by a confirmatory method such as Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS) or permitting laboratories to establish quality control procedures. The assay provides only a preliminary analytical test result. A more specific alternative chemical method must be used to obtain a confirmed analytical result. Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS) is the preferred confirmatory method. Clinical and professional judgment should be applied to any drug of abuse test result, particularly when preliminary positive results are used. For In Vitro Diagnostic Use Only.
Device Story
DRI™ Tricyclics Serum Tox Assay is a homogeneous enzyme immunoassay for detecting tricyclic antidepressants (TCAs) in serum, plasma, or urine. Input: patient sample; Principle: competitive binding between drug in sample and enzyme-labeled drug (G6PDH) for fixed antibody sites; Output: spectrophotometric measurement at 340 nm (NAD to NADH conversion). Higher drug concentration correlates with higher enzyme activity. Used in clinical laboratories by trained professionals. Results are preliminary; positive findings require confirmation via LC-MS/MS. Assists clinicians in managing suspected drug overdose cases.
Clinical Evidence
No clinical trials performed. Evidence consists of analytical performance studies: precision (n=80 per level), linearity, and method comparison against LC-MS/MS using 117 serum and 100 urine clinical specimens. Interference testing evaluated cross-reactivity with various drugs and endogenous substances. Results confirm performance characteristics consistent with the predicate.
Technological Characteristics
Homogeneous enzyme immunoassay; two-reagent kit (Antibody/Substrate and Enzyme Conjugate) containing sheep polyclonal anti-tricyclics antibodies, G6PDH, G6P, and NAD in Tris buffer with sodium azide. Spectrophotometric detection at 340 nm. Designed for use on the Architect c4000 clinical chemistry analyzer. Standards referenced include CLSI EP05-A3, EP07-ED3, EP09c-ED3, EP25-A, EP35-ED1, and EP12-A2.
Indications for Use
Indicated for qualitative and/or semiquantitative detection of tricyclic antidepressants (TCAs) in human serum, plasma, or urine for patients suspected of drug overdose at a 300 ng/mL cutoff. Rx only.
Regulatory Classification
Identification
A tricyclic antidepressant drugs test system is a device intended to measure any of the tricyclic antidepressant drugs in serum. The tricyclic antidepressant drugs include imipramine, desipramine, amitriptyline, nortriptyline, protriptyline, and doxepin. Measurements obtained by this device are used in the diagnosis and treatment of chronic depression to ensure appropriate therapy.
Special Controls
*Classification.* Class II (special controls). A tricyclic antidepressant drugs test system is not exempt if it is intended for any use other than employment or insurance testing or is intended for Federal drug testing programs. The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 862.9, provided the test system is intended for employment and insurance testing and includes a statement in the labeling that the device is intended solely for use in employment and insurance testing, and does not include devices intended for Federal drug testing programs (*e.g.,* programs run by the Substance Abuse and Mental Health Services Administration (SAMHSA), the Department of Transportation (DOT), and the U.S. military).
Predicate Devices
- Tricyclic Serum Tox EIA Assay (K983268)
Related Devices
- K231020 — Alinity c Tricyclic Antidepressants Reagent Kit · Microgenics Corporation · Nov 17, 2023
- K983268 — MODIFICATION OF TRICYCLIC SERUM TOX EIA ASSAY · Diagnostic Reagents, Inc. · Nov 18, 1998
- K173963 — DRI Benzodiazepine Assay · Microgenics Corporation · Feb 21, 2018
Submission Summary (Full Text)
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FDA
U.S. FOOD & DRUG
ADMINISTRATION
# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
ASSAY ONLY
## I Background Information:
A 510(k) Number
K213875
B Applicant
Microgenics Corporation
C Proprietary and Established Names
DRI™ Tricyclics Serum Tox Assay
D Regulatory Information
| Product Code(s) | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| LFH | Class II | 21 CFR 862.3910 - Tricyclic Antidepressant Drugs Test System | TX - Clinical Toxicology |
## II Submission/Device Overview:
A Purpose for Submission:
New device (assay)
B Measurand:
Nortriptyline
C Type of Test:
Qualitative/Semiquantitative - Enzymatic Immunoassay
Food and Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993-0002
www.fda.gov
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III Intended Use/Indications for Use:
A Intended Use(s):
See Indications for Use below.
B Indication(s) for Use:
The DRI™ Tricyclics Serum Tox Assay is a homogenous enzyme immunoassay intended for the qualitative and/or semiquantitative determination of the presence of tricyclic antidepressants (TCAs) in human serum, plasma, or urine of patients at a cutoff concentration of 300 ng/mL in patients suspected of drug overdose.
The semi-quantitative mode is for the purpose of enabling laboratories to determine an appropriate dilution of the specimen for confirmation by a confirmatory method such as Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS) or permitting laboratories to establish quality control procedures.
The assay provides only a preliminary analytical test result. A more specific alternative chemical method must be used to obtain a confirmed analytical result. Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS) is the preferred confirmatory method.
Clinical and professional judgment should be applied to any drug of abuse test result, particularly when preliminary positive results are used.
For In Vitro Diagnostic Use Only.
C Special Conditions for Use Statement(s):
Rx - For Prescription Use Only
D Special Instrument Requirements:
Architect c4000 Clinical Chemistry Analyzer
IV Device/System Characteristics:
A Device Description:
The DRI™ Tricyclics Serum Tox Assay is a homogeneous enzyme immunoassay used to detect tricyclic antidepressants in serum, plasma, or urine. The DRI™ Tricyclics Serum Tox assay is supplied as a two liquid reagent kit (Reagent A and Reagent E). They are bottled separately within the same kit, as described below:
K213875 - Page 2 of 18
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- Antibody/Substrate Reagent (Reagent A) 1 bottle of 25 mL (1 x 25 mL): Contains polyclonal anti-tricyclics antibodies (sheep), glucose-6-phosphate (G6P), and nicotinamide adenine dinucleotide (NAD) in Tris buffer with sodium azide as a preservative.
- Enzyme Conjugate Reagent (Reagent E) 1 bottle of 8 mL (1 x 8 mL): Contains glucose-6-phosphate dehydrogenase (G6PDH) labeled with nortriptyline in Tris buffer with sodium azide as a preservative.
## B Principle of Operation:
The test is based on the competition of an enzyme, glucose-6-phosphate dehydrogenase (G6PDH), labeled-drug and the drug from the sample for a fixed amount of specific antibody binding sites. In the absence of the drug from the sample, the specific antibody binds the enzyme-labeled drug and the enzyme activity is inhibited. This phenomenon creates a direct relationship between drug concentration in the sample and the enzyme activity. The enzyme activity is determined spectrophotometrically at 340 nm by measuring its ability to convert nicotinamide adenine dinucleotide (NAD) to NADH.
## V Substantial Equivalence Information:
### A Predicate Device Name(s):
Tricyclic Serum Tox Eia Assay
### B Predicate 510(k) Number(s):
K983268
### C Comparison with Predicate(s):
| Device & Predicate Device(s): | K213875 | K983268 |
| --- | --- | --- |
| Device Trade Name | DRI™ Tricyclics Serum Tox Assay | Tricyclic Serum Tox EIA Assay |
| General Device Characteristic Similarities | | |
| Intended Use/Indications For Use | Intended to be used for qualitative and semiquantitative determination of tricyclic antidepressants in serum, plasma or urine of patients suspected of drug overdose. | Same |
| Measurand | Nortriptyline | Same |
| Sample Matrix | Serum, Plasma, Urine | Same |
| Cut-Off | 300 ng/mL | Same |
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| General Device Characteristic Differences | | |
| --- | --- | --- |
| Antibody | Sheep polyclonal antibodies | Monoclonal antibodies |
## VI Standards/Guidance Documents Referenced:
- Evaluation of Precision of Quantitative Measurement Procedures; Approved Guideline-Third Edition. (Clinical and Laboratory Standards Institute (CLSI) EP05-A3).
- Interference Testing in Clinical Chemistry (CLSI EP07-ED3).
- Measurement Procedure Comparison and Bias Estimation Using Patient Samples (CLSI EP09c-ED3).
- Evaluation of Stability of In Vitro Diagnostic Reagents; Approved Guideline (CLSI EP25-A).
- Assessment of Equivalence or Suitability of Specimen Types for Medical Laboratory Measurement Procedures. (CLSI EP35-ED1).
- User Protocol for Evaluation of Qualitative Test Performance Approved Guideline – Second Edition (CLSI EP12-A2).
## VII Performance Characteristics (if/when applicable):
### A Analytical Performance:
1. Precision/Reproducibility:
**Repeatability**
Samples were prepared by spiking Nortriptyline into drug-free serum and drug-free urine at the cutoff as well as 25%, 50%, 75%, and 100% above and below the cutoff and tested in duplicate (n=2) twice per day for 20 days (total n=80 for each level), in both qualitative and semi-quantitative modes. The results are shown below.
Table #1 – Serum:
| Spiked Concentration (ng/mL)* | % of Cutoff | Total Precision (n=80) – Serum | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | # of Determinants | Qualitative Immunoassay Results (Negative/Positive) | Semi-quantitative Immunoassay Results (Negative/Positive) | Semi-quantitative SD results | Semi-quantitative CV% results |
| 0 | -100 | 80 | 80/0 | 80/0 | N/A | N/A |
| 75 | -75 | 80 | 80/0 | 80/0 | 4.40 | 5.36 |
| 150 | -50 | 80 | 80/0 | 80/0 | 4.19 | 2.42 |
| 225 | -25 | 80 | 80/0 | 80/0 | 4.22 | 1.68 |
| 300 | 100 | 80 | 10/70 | 19/61 | 17.29 | 5.34 |
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| Spiked Concentration (ng/mL)* | % of Cutoff | Total Precision (n=80) – Serum | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | # of Determinants | Qualitative Immunoassay Results (Negative/ Positive) | Semi-quantitative Immunoassay Results (Negative/ Positive) | Semi-quantitative SD results | Semi-quantitative CV% results |
| 375 | +25 | 80 | 0/80 | 0/80 | 16.59 | 3.92 |
| 450 | +50 | 80 | 0/80 | 0/80 | 19.15 | 3.94 |
| 525 | +75 | 80 | 0/80 | 0/80 | 47.37 | 8.25 |
| 600 | +100 | 80 | 0/80 | 0/80 | 43.10 | 6.28 |
*Approximate concentrations
Table #2 - Urine:
| Spiked Concentration (ng/mL)* | % of Cutoff | Total Precision (n=80) - Urine | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | # of Determinants | Qualitative Immunoassay Results (Negative/ Positive) | Semi-quantitative Immunoassay Results (Negative/ Positive) | Semi-quantitative SD results | Semi-quantitative CV% results |
| 0 | -100 | 80 | 80/0 | 80/0 | N/A | N/A |
| 75 | -75 | 80 | 80/0 | 80/0 | 4.62 | 5.96 |
| 150 | -50 | 80 | 80/0 | 80/0 | 7.19 | 4.45 |
| 225 | -25 | 80 | 80/0 | 80/0 | 9.62 | 4.08 |
| 300 | 100 | 80 | 68/12 | 73/7 | 11.04 | 3.75 |
| 375 | +25 | 80 | 0/80 | 0/80 | 24.41 | 6.12 |
| 450 | +50 | 80 | 0/80 | 0/80 | 18.65 | 4.13 |
| 525 | +75 | 80 | 0/80 | 0/80 | 46.66 | 8.89 |
| 600 | +100 | 80 | 0/80 | 0/80 | 45.15 | 7.63 |
*Approximate concentrations
## Reproducibility:
Samples were prepared by spiking Nortriptyline into drug-free serum and drug-free urine at the cutoff as well as at 25%, 50%, 75%, and 100% above and below the cutoff. Spiked samples were tested as 1 run per day, 5 replicates per run for a total of 5 days in qualitative and semi-quantitative modes on 3 different instruments of the same model. The results of the reproducibility study are shown below:
K213875 - Page 5 of 18
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Table #3 - Serum:
| Spiked Concentration (ng/mL)* | % of Cutoff | Total Precision (n=75) - Serum | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | # of Determinants | Qualitative Immunoassay Results (Negative/ Positive) | Semi-quantitative Immunoassay Results (Negative/ Positive) | Semi-quantitative SD results | Semi-quantitative CV% results |
| 0 | -100 | 75 | 75/0 | 75/0 | N/A | N/A |
| 75 | -75 | 75 | 75/0 | 75/0 | 5.26 | 6.66 |
| 150 | -50 | 75 | 75/0 | 75/0 | 4.00 | 2.39 |
| 225 | -25 | 75 | 75/0 | 75/0 | 4.36 | 1.76 |
| 300 | 100 | 75 | 30/45 | 29/46 | 19.24 | 6.11 |
| 375 | +25 | 75 | 0/75 | 0/75 | 22.23 | 5.40 |
| 450 | +50 | 75 | 0/75 | 0/75 | 21.06 | 4.41 |
| 525 | +75 | 75 | 0/75 | 0/75 | 43.78 | 7.87 |
| 600 | +100 | 75 | 0/75 | 0/75 | 43.77 | 6.54 |
*Approximate concentrations
Table #4 - Urine:
| Spiked Concentration (ng/mL)* | % of Cutoff | Total Precision (n=75) - Urine | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | # of Determinants | Qualitative Immunoassay Results (Negative/ Positive) | Semi-quantitative Immunoassay Results (Negative/ Positive) | Semi-quantitative SD results | Semi-quantitative CV% results |
| 0 | -100 | 75 | 75/0 | 75/0 | N/A | N/A |
| 75 | -75 | 75 | 75/0 | 75/0 | 3.34 | 4.30 |
| 150 | -50 | 75 | 75/0 | 75/0 | 4.60 | 2.82 |
| 225 | -25 | 75 | 75/0 | 75/0 | 6.90 | 2.86 |
| 300 | 100 | 75 | 61/14 | 66/9 | 12.05 | 4.01 |
| 375 | +25 | 75 | 0/75 | 0/75 | 23.21 | 5.85 |
| 450 | +50 | 75 | 0/75 | 0/75 | 23.96 | 5.28 |
| 525 | +75 | 75 | 0/75 | 0/75 | 39.74 | 7.73 |
| 600 | +100 | 75 | 0/75 | 0/75 | 42.36 | 7.86 |
*Approximate concentrations
2. Linearity:
Drug-free serum or drug-free urine was spiked with Nortriptyline to the concentration of the high calibrator level and diluted with drug-free serum or drug-free urine to generate 9 intermediate levels. Five (5) replicates of each sample using one (1) lot of reagents, calibrators, and controls were run in semi-quantitative mode and the average was used to determine percent recovery compared to the expected target value.
K213875 - Page 6 of 18
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Table #5: Linearity Results Table
| Expected Concentration (ng/mL) | Observed Mean Concentration for Serum (ng/mL) | Observed Mean Concentration for Urine (ng/mL) | Range of Recovery (%) | |
| --- | --- | --- | --- | --- |
| | | | Serum | Urine |
| 0 | 7 | 8 | NA | NA |
| 125 | 121 | 148 | 96-115* | 94-118* |
| 250 | 242 | 271 | | |
| 375 | 385 | 383 | | |
| 500 | 479 | 470 | | |
| 625 | 720 | 620 | | |
| 750 | 839 | 741 | | |
| 875 | 913 | 838 | | |
| 1000 | 1046 | 946 | | |
*Excluding the observed mean concentration at the $1^{st}$ Level (0 ng/mL).
# 3. Analytical Specificity/Interference:
The cross-reactivity of tricyclic antidepressants as well as their metabolites was evaluated by adding known amounts of each compound to drug-free serum and urine. The specificity (cross-reactivity) study was performed using one lot of reagents, calibrators and controls in both qualitative and semi-quantitative modes. Two (2) replicates of each cross-reactant sample were run in qualitative and semi-quantitative modes on the Architect c4000 clinical chemistry analyzer. Percent cross-reactivity was calculated as (cut-off concentration / lowest concentration observed that provides a reliably positive result) x 100. Results are summarized in tables #6 and #7 below:
Table #6: Cross Reactivity of Tricyclic antidepressants and structurally related compounds - Serum
| Tricyclic Antidepressants & Structurally related compounds | Concentration tested (ng/mL) | Cross-reactivity (%) |
| --- | --- | --- |
| 2 -Hydroxy Imipramine | 1,300 | 23.1 |
| 7-Hydroxy Quetiapine | 100,000 | <0.3 |
| 7-Hydroxy Amoxapine solution | 100,000 | <0.3 |
| 8-Hydroxy Amoxapine solution | 100,000 | <0.3 |
| 10-Hydroxyamitriptyline | 1,000 | 30.0 |
| Alimemazine | 12,000 | 2.5 |
| Amitriptyline | 300 | 85.7 |
| Amoxapine | 125,000 | 0.2 |
| Blonanserin | 100,000 | <0.3 |
| Chlorpromazine | 525 | 57.1 |
| Clomipramine | 300 | 100.0 |
| Clozapine | 100,000 | <0.3 |
| Cyclobenzaprine | 450 | 66.7 |
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| Tricyclic Antidepressants & Structurally related compounds | Concentration tested (ng/mL) | Cross-reactivity (%) |
| --- | --- | --- |
| Desipramine | 250 | 120.0 |
| Desloratadine | 100,000 | <0.3 |
| Diphenhydramine | 60,000 | 0.5 |
| Dosulepin | 475 | 63.2 |
| Doxepin | 600 | 50.0 |
| Fluoxentine | 100,000 | <0.3 |
| Fluphenazine | 2,000 | 15.0 |
| Haloperidol | 100,000 | <0.3 |
| Imipramine | 190 | 157.9 |
| Loratadine | 100,000 | <0.3 |
| Lofepramine | 430 | 69.8 |
| Loxapine Succinate | 100,000 | <0.3 |
| Maprotiline | 100,000 | 0.3 |
| Mianserin | 100,000 | <0.3 |
| Mirtazapine | 100,000 | <0.3 |
| N-Desmethylclozapine | 100,000 | <0.3 |
| N-Desmethyltrimpramine | 350 | 85.7 |
| NefazodoneN-Desmethylmirtazapine | 100,000 | <0.3 |
| Nefazodone N-Desmethylmirtazapine | 100,000 | <0.3 |
| Norclomipramine Hydrochloride | 375 | 80.0 |
| Nordoxepin Hydrochloride | 1,750 | 17.1 |
| Normaprotiline | 100,000 | 0.3 |
| Nortriptyline | 300 | 100.0 |
| Olanzapine | 100,000 | <0.3 |
| Opipramol HCL | 400 | 85.7 |
| Praoxetine | 100,000 | <0.3 |
| Perphenazine | 450 | 66.7 |
| Phenoxybenzanmine | 100,000 | <0.3 |
| Promazine | 400 | 75.0 |
| Promethazine | 20,000 | 1.5 |
| Protriptyline | 450 | 66.7 |
| Quetiapine Fumarate | 50,000 | 0.6 |
| Risperidone | 100,000 | <0.3 |
| Sertraline | 100,000 | <0.3 |
| Thioridazine | 6,000 | 5.0 |
| Thiothixene | 100,000 | <0.3 |
| Tianeptine | 100,000 | <0.3 |
| Trazodone | 100,000 | 0.3 |
| Trimipramine | 390 | 76.9 |
| Ziprasidone | 100,000 | <0.3 |
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Table #7: Cross Reactivity of Tricyclic antidepressants and structurally related compounds - Urine
| Tricyclic Antidepressants & Structurally related compounds | Concentration tested (ng/mL) | Cross-reactivity (%) |
| --- | --- | --- |
| 2 -Hydroxy Imipramine | 1,000 | 30.0 |
| 7-Hydroxy Quetiapine | 100,000 | <0.3 |
| 7-Hydroxy Amoxapine solution | 100,000 | <0.3 |
| 8-Hydroxy Amoxapine solution | 100,000 | <0.3 |
| 10-Hydroxyamitriptyline | 1,000 | 30.0 |
| Alimemazine | 12,000 | 2.5 |
| Amitriptyline | 300 | 100 |
| Amoxapine | 100,000 | 0.2 |
| Blonanserin | 100,000 | <0.3 |
| Chlorpromazine | 600 | 50.0 |
| Clomipramine | 350 | 85.7 |
| Clozapine | 100,000 | <0.3 |
| Cyclobenzaprine | 500 | 60.0 |
| Desipramine | 250 | 120 |
| Desloratadine | 100,000 | <0.3 |
| Diphenhydramine | 30,000 | 1.0 |
| Dosulepin | 550 | 54.5 |
| Doxepin | 600 | 50.0 |
| Fluoxetine | 100,000 | <0.3 |
| Fluphenazine | 2,000 | 15.0 |
| Haloperidol | 100,000 | <0.3 |
| Imipramine | 250 | 120.0 |
| Loratadine | 100,000 | <0.3 |
| Lofepramine | 460 | 65.2 |
| Loxapine Succinate | 100,000 | 0.3 |
| Maprotiline | 100,000 | 0.3 |
| Mianserin | 100,000 | <0.3 |
| Mirtazapine | 100,000 | <0.3 |
| N-Desmethylclozapine | 100,000 | <0.3 |
| N-Desmethyltrimpramine | 325 | 92.3 |
| N-Desmethylmirtazapine | 100,000 | <0.3 |
| Nefazodone | 100,000 | <0.3 |
| Norclomipramine Hydrochloride | 450 | 66.7 |
| Nordoxepin Hydrochloride | 1,750 | 17.1 |
| Normaprotiline | 100,000 | 0.3 |
| Nortriptyline | 300 | 100.0 |
| Olanzapine | 100,000 | <0.3 |
| Opipramol HCL | 350 | 85.7 |
| Praoxetine | 100,000 | <0.3 |
| Perphenazine | 650 | 46.2 |
| Phenoxybenzanmine | 100,000 | <0.3 |
| Promazine | 410 | 73.2 |
| Promethazine | 15,000 | 2.0 |
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A specificity study of structurally unrelated compounds/or concurrently used drugs was evaluated by adding known amounts of each compound to low and high controls (225 and 375 ng/mL) in serum and urine. The study was performed using one lot of reagents, calibrators and controls in both qualitative and semi-quantitative modes. Two (2) replicates of each cross-reactant sample were run in qualitative and semi-quantitative modes on the Architect c4000 clinical chemistry analyzer. Results are summarized in tables #8 and #9 below:
Table #8: Structurally unrelated compounds – Serum
| Structurally unrelated compounds | Serum | | |
| --- | --- | --- | --- |
| | Concentration tested (ng/mL) | Low Control - 25% of cutoff (225 ng/mL) | High Control +25% of cutoff (375 ng/mL) |
| 11-nor-Δ9-THC-COOH (11-Nor-9-carboxy-THC) | 100,000 | Negative | Positive |
| 6-Acetyl morphine | 75,000 | Negative | Positive |
| Acetaminophen | 100,000 | Negative | Positive |
| Acetylsalicylic acid | 100,000 | Negative | Positive |
| Amisulpride | 100,000 | Negative | Positive |
| Amoxicillin | 100,000 | Negative | Positive |
| Amphetamine | 100,000 | Negative | Positive |
| Benzotropine Methane Sulfonate | 3,000 | Negative | Positive |
| Benzoylecgonine | 100,000 | Negative | Positive |
| Brompheniramine | 3,000 | Negative | Positive |
| Caffeine | 100,000 | Negative | Positive |
| Carbamazepine | 3,000 | Negative | Positive |
| Carbamazepine Epoxide | 10,000 | Negative | Positive |
| Chloroquine Phosphate | 100,000 | Negative | Positive |
| Cimetidine | 100,000 | Negative | Positive |
| Cocaine | 75,000 | Negative | Positive |
| Codeine | 100,000 | Negative | Positive |
| Dextromethorphan | 100,000 | Negative | Positive |
| Diacetylmorphine (Heroin) | 100,000 | Negative | Positive |
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| Structurally unrelated compounds | Serum | | |
| --- | --- | --- | --- |
| | Concentration tested (ng/mL) | Low Control - 25% of cutoff (225 ng/mL) | High Control +25% of cutoff (375 ng/mL) |
| Diazepam | 100,000 | Negative | Positive |
| Digoxin | 100,000 | Negative | Positive |
| Dihydrocodeine | 100,000 | Negative | Positive |
| EDDP Perchlorate | 100,000 | Negative | Positive |
| EMDP-HCL | 100,000 | Negative | Positive |
| Fentanyl | 25,000 | Negative | Positive |
| Glutethimide | 100,000 | Negative | Positive |
| Hydrocodone | 100,000 | Negative | Positive |
| Hydrocortisone | 100,000 | Negative | Positive |
| Hydromorphone | 100,000 | Negative | Positive |
| Hydroxyzine | 3,000 | Negative | Positive |
| Ibuprofen | 100,000 | Negative | Positive |
| Levorphanol-D3 | 100,000 | Negative | Positive |
| Meperidine | 100,000 | Negative | Positive |
| Methadone | 3,000 | Negative | Positive |
| Methamphetamine | 100,000 | Negative | Positive |
| Methaqualone | 500 | Negative | Positive |
| Methsuximide | 75,000 | Negative | Positive |
| Methylphenidate | 100,000 | Negative | Positive |
| Morphine | 100,000 | Negative | Positive |
| Morphine-3β-glucuronide | 100,000 | Negative | Positive |
| Morphine-6β-glucuronide | 100,000 | Negative | Positive |
| Nalbuphine | 100,000 | Negative | Positive |
| Nalorphine | 100,000 | Negative | Positive |
| Naloxone | 100,000 | Negative | Positive |
| Naltrexone | 100,000 | Negative | Positive |
| Naproxen | 100,000 | Negative | Positive |
| Norcodeine | 100,000 | Negative | Positive |
| Nordiazepam | 100,000 | Negative | Positive |
| Norethindrone | 100,000 | Negative | Positive |
| Norhydrocone | 100,000 | Negative | Positive |
| Noroxycodone | 100,000 | Negative | Positive |
| Noroxymorphone | 100,000 | Negative | Positive |
| Norpropoxyphene | 75,000 | Negative | Positive |
| Oxaprozin | 100,000 | Negative | Positive |
| Oxazepam | 100,000 | Negative | Positive |
| Oxycodone | 100,000 | Negative | Positive |
| Oxymorphone | 100,000 | Negative | Positive |
| PCP | 50,000 | Negative | Positive |
| Phenobarbital | 100,000 | Negative | Positive |
| Phenytoin | 100,000 | Negative | Positive |
| Primidone | 100,000 | Negative | Positive |
| Procyclidine | 100,000 | Negative | Positive |
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Table #9: Structurally unrelated compounds – Urine:
| Structurally unrelated compounds | Urine | | |
| --- | --- | --- | --- |
| | Concentration tested (ng/mL) | Low Control - 25% of cutoff (225 ng/mL) | High Control +25% of cutoff (375 ng/mL) |
| 11-nor-Δ9-THC-COOH (11-Nor-9-carboxy-THC) | 100,000 | Negative | Positive |
| 6-Acetyl morphine | 100,000 | Negative | Positive |
| Acetaminophen | 100,000 | Negative | Positive |
| Acetylsalicylic acid | 100,000 | Negative | Positive |
| Amisulpride | 100,000 | Negative | Positive |
| Amoxicillin | 100,000 | Negative | Positive |
| Amphetamine | 100,000 | Negative | Positive |
| Benzotropine Methane Sulfonate | 7,000 | Negative | Positive |
| Benzoylecgonine | 100,000 | Negative | Positive |
| Brompheniramine | 5,000 | Negative | Positive |
| Caffeine | 100,000 | Negative | Positive |
| Carbamazepine | 5,000 | Negative | Positive |
| Carbamazepine Epoxide | 30,000 | Negative | Positive |
| Chloroquine Phosphate | 100,000 | Negative | Positive |
| Cimetidine | 100,000 | Negative | Positive |
| Cocaine | 100,000 | Negative | Positive |
| Codeine | 100,000 | Negative | Positive |
| Dextromethorphan | 100,000 | Negative | Positive |
| Diacetylmorphine (Heroin) | 100,000 | Negative | Positive |
| Diazepam | 100,000 | Negative | Positive |
| Digoxin | 100,000 | Negative | Positive |
| Dihydrocodeine | 100,000 | Negative | Positive |
| EDDP Perchlorate | 100,000 | Negative | Positive |
| EMDP-HCL | 100,000 | Negative | Positive |
| Fentanyl | 25,000 | Negative | Positive |
| Glutethimide | 100,000 | Negative | Positive |
| Hydrocodone | 100,000 | Negative | Positive |
| Hydrocortisone | 100,000 | Negative | Positive |
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| Structurally unrelated compounds | Urine | | |
| --- | --- | --- | --- |
| | Concentration tested (ng/mL) | Low Control - 25% of cutoff (225 ng/mL) | High Control +25% of cutoff (375 ng/mL) |
| Hydromorphone | 100,000 | Negative | Positive |
| Hydroxyzine | 5,000 | Negative | Positive |
| Ibuprofen | 100,000 | Negative | Positive |
| Levorphanol-D3 | 100,000 | Negative | Positive |
| Levothyroxine | 100,000 | Negative | Positive |
| Meperidine | 25,000 | Negative | Positive |
| Methadone | 75,000 | Negative | Positive |
| Methamphetamine | 100,000 | Negative | Positive |
| Methaqualone | 1,000 | Negative | Positive |
| Methsuximide | 75,000 | Negative | Positive |
| Methylphenidate | 100,000 | Negative | Positive |
| Morphine | 100,000 | Negative | Positive |
| Morphine-3β-glucuronide | 100,000 | Negative | Positive |
| Morphine-6β-glucuronide | 100,000 | Negative | Positive |
| Nalbuphine | 100,000 | Negative | Positive |
| Nalorphine | 100,000 | Negative | Positive |
| Naloxone | 100,000 | Negative | Positive |
| Naltrexone | 100,000 | Negative | Positive |
| Naproxen | 100,000 | Negative | Positive |
| Norcodeine | 100,000 | Negative | Positive |
| Nordiazepam | 100,000 | Negative | Positive |
| Norethindrone | 100,000 | Negative | Positive |
| Norhydrocone | 75,000 | Negative | Positive |
| Noroxycodone | 100,000 | Negative | Positive |
| Noroxymorphone | 100,000 | Negative | Positive |
| Norpropoxyphene | 75,000 | Negative | Positive |
| Oxaprozin | 100,000 | Negative | Positive |
| Oxazepam | 100,000 | Negative | Positive |
| Oxycodone | 100,000 | Negative | Positive |
| Oxymorphone | 100,000 | Negative | Positive |
| PCP | 75,000 | Negative | Positive |
| Phenobarbital | 100,000 | Negative | Positive |
| Phenytoin | 100,000 | Negative | Positive |
| Primidone | 100,000 | Negative | Positive |
| Procyclidine | 100,000 | Negative | Positive |
| Propoxyphene | 100,000 | Negative | Positive |
| Secobarbital | 100,000 | Negative | Positive |
| Tapentadol | 100,000 | Negative | Positive |
| Temazepam | 100,000 | Negative | Positive |
| Triprolidine | 100,000 | Negative | Positive |
| Valproic Acid | 100,000 | Negative | Positive |
| Venlafaxine | 100,000 | Negative | Positive |
| Verapamil | 100,000 | Negative | Positive |
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When Carbamazepine was added to near cutoff negative (225 ng/mL) samples at concentrations of 4,000 ng/mL in serum, positive results were observed. Device labeling includes the following limitation: "Patient samples containing tricyclic antidepressants in the presence of carbamazepine may yield falsely elevated results in the TCA immunoassay. Results should always be assessed in conjunction with the patient's medical history, clinical examinations, and other clinicopathological findings."
## Interference Testing of exogenous and endogenous compounds
Interference from various compounds was evaluated by adding known amounts of each compound to drug free serum and urine samples containing near cutoff negative (225 ng/mL) and near cutoff positive (375 ng/mL) concentrations of Nortriptyline. Testing was performed in both qualitative and semiquantitative modes. The compounds listed in the table below did not cause any positive or negative interference at the concentrations shown:
Table #10: Interference Test of structurally unrelated compounds - Serum
| Compounds | Tested Concentration (mg/dL) |
| --- | --- |
| Bilirubin (Conjugated) | 40 |
| Bilirubin (Unconjugated) | 40 |
| Hemoglobin | 1000 |
| Albumin | 7500 |
| γ-globulin | 5000 |
| Rh Factor | 1300 IU |
| Triglycerides | 1500 |
| Cholesterol | 1400 |
Table #11: Interference Test of structurally unrelated compounds – Urine
| Compounds | Test Concentration (mg/dL) |
| --- | --- |
| Ascorbic Acid | 150 |
| Caffeine | 5 |
| Creatinine | 400 |
| Ethanol | 1000 |
| Galactose | 5 |
| Glucose | 1000 |
| Hemoglobin | 150 |
| Human Serum Albumin | 200 |
| Ibuprofen | 10 |
| Oxalic acid | 50 |
| Riboflavin | 3 |
| Sodium Chloride | 1000 |
| Urea | 1000 |
## Interference Testing of Specific Gravity and pH (Urine):
Drug free urine samples with specific gravity ranging in value from 1.004 to 1.030 were split and spiked with Nortriptyline to near cutoff negative (225 ng/mL) and near cutoff positive (375 ng/mL) concentrations. Samples were evaluated in qualitative and semi-quantitative modes. The following specific gravities did not cause any positive or negative interference:
K213875 - Page 14 of 18
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1.004, 1.006, 1.008, 1.010, 1.011, 1.012, 1.013, 1.016, 1.022 and 1.030.
Interference from pH was evaluated by adjusting the pH of urine samples containing near cutoff negative (225 ng/mL) and near cutoff positive (375 ng/mL) concentrations of Nortriptyline. The following pH values did not cause any positive or negative interference: 3, 4, 5, 6, 7, 8, 9, 10 and 11.
## 4. Assay Reportable Range:
Not applicable.
## 5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
Traceability: The primary calibrators are traceable to the certified reference material Nortriptyline purchased from a commercial source. The concentration of the primary calibrator stocks is confirmed by LC-MS/MS from independent laboratories.
## 6. Detection Limit:
Not applicable.
## 7. Assay Cut-Off:
Characterization of how the device performs analytically around the claimed cutoff concentration is described in the precision section, VII.A.1. above.
## B Comparison Studies:
## 1. Method Comparison with Predicate Device:
One hundred seventeen serum clinical specimens and one hundred urine clinical specimens were tested using the DRI™ Tricyclics Serum Tox Assay on the Architect c4000 clinical chemistry analyzer and confirmed by LC-MS/MS. The results are presented below:
Table #12: Qualitative Accuracy Study with LC-MS/MS as Reference Method – Serum
| Candidate Device Results | Negative by LC-MS/MS | < 50% of Cutoff concentration by LC-MS/MS (< 150 ng/mL) | Near Cutoff Negative (Between 50% below the cutoff and the cutoff concentration as determined by LC-MS/MS) (150-299 ng/mL) | Near Cutoff Positive (Between the cutoff and 50% above the cutoff concentration as determined by LC-MS/MS) (300-450 ng/mL) | High Positives (Greater than 50% above cutoff concentration) (> 450 ng/mL) |
| --- | --- | --- | --- | --- | --- |
| Positive | 0 | 1^{1} | 0 | 31 | 25 |
| Negative | 1 | 35 | 24 | 0 | 0 |
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Table #13: Qualitative Accuracy Study with LC-MS/MS as Reference Method - Urine
| Candidate Device Results | Negative by LC-MS/MS | < 50% of Cutoff concentration by LC-MS/MS (< 150 ng/mL) | Near Cutoff Negative (Between 50% below the cutoff and the cutoff concentration as determined by LC-MS/MS) (150-299 ng/mL) | Near Cutoff Positive (Between the cutoff and 50% above the cutoff concentration as determined by LC-MS/MS) (300-450 ng/mL) | High Positives (Greater than 50% above cutoff concentration) (> 450 ng/mL) |
| --- | --- | --- | --- | --- | --- |
| Positive | 0 | 0 | 2 | 7 | 42 |
| Negative | 22 | 11 | 15 | 1 | 0 |
Table #14: Semi-quantitative Accuracy Study with LC-MS/MS as Reference Method - Serum
| Candidate Device Results | Negative by LC-MS/MS | < 50% of Cutoff concentration by LC-MS/MS (< 150 ng/mL) | Near Cutoff Negative (Between 50% below the cutoff and the cutoff concentration as determined by LC-MS/MS) (150-299 ng/mL) | Near Cutoff Positive (Between the cutoff and 50% above the cutoff concentration as determined by LC-MS/MS) (300-450 ng/mL) | High Positives (Greater than 50% above cutoff concentration) (> 450 ng/mL) |
| --- | --- | --- | --- | --- | --- |
| Positive | 0 | 2² | 0 | 31 | 25 |
| Negative | 1 | 34 | 24 | 0 | 0 |
Table #15: Semi-quantitative Accuracy Study with LC-MS/MS as Reference Method - Urine
| Candidate Device Results | Negative by LC-MS/MS | < 50% of Cutoff concentration by LC-MS/MS (< 150 ng/mL) | Near Cutoff Negative (Between 50% below the cutoff and the cutoff concentration as determined by LC-MS/MS) (150-299 ng/mL) | Near Cutoff Positive (Between the cutoff and 50% above the cutoff concentration as determined by LC-MS/MS) (300-450 ng/mL) | High Positives (Greater than 50% above cutoff concentration) (> 450 ng/mL) |
| --- | --- | --- | --- | --- | --- |
| Positive | 0 | 0 | 2 | 7 | 42 |
| Negative | 22 | 11 | 15 | 1 | 0 |
Table #16: Discordant Samples:
| Sample ID | Sample Type | EIA | | LC-MS/MS value (ng/ml) |
| --- | --- | --- | --- | --- |
| | | Qualitative | Semi-Quantitative | |
| APP9489-22 | Serum | Negative | Positive | 110 |
| APP9474-21,2 | Serum | Positive | Positive | 120 |
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Sample APP9489-2 contains the following parent Tricyclic antidepressants: Amitriptyline at 8.08 ng/mL, Imipramine at 18.35 ng/mL, Desipramine at 46.35 ng/mL, and Nortriptyline at 17 ng/mL by LC-MS/MS which cross-react at 100%, 158% 120% and 100% respectively by immunoassay. In addition to the tricyclic antidepressants identified, another cross-reacting drug compound was detected in the sample, as below:
| Drug Class | Drug Name | LC-MS/MS value (ng/mL) |
| --- | --- | --- |
| Antiepileptic drugs | Carbamazepine | 4275 |
Sample APP9474-2 contains Amitriptyline at 9.08 ng/mL, Imipramine at 19.9 ng/mL and Desipramine at 49.8 ng/mL, and Nortriptyline at 19.65 ng/mL by LC-MS/MS and cross-reacts at 100%, 158% 120%, and 100% by immunoassay accordingly. In addition to the tricyclic antidepressants identified, another cross-reacting drug compound was detected in the sample, as below:
| Drug Class | Drug Name | LC-MS/MS value (ng/mL) |
| --- | --- | --- |
| Antiepileptic drugs | Carbamazepine | 5285 |
## 2. Matrix Comparison:
50 Patient specimens were run in both qualitative and semi-quantitative modes. The testing specimens consisted of matched sets of; Serum, K2-EDTA, K3-EDTA, Lithium Heparin, Sodium Citrate, Potassium Oxalate samples; as well as 45 secondary matched sets of Serum and Sodium Heparin samples. The Nortriptyline concentrations of the samples tested spanned from approximately 135 ng/mL to approximately 930 ng/mL. The study demonstrates Nortriptyline concentrations obtained in different test plasma matrices with different anticoagulants are equivalent to those measured in the primary or control matrix, serum across the assay's measuring range.
Table #17: Matrix Equivalency results in qualitative and semi-quantitative mode
| Serum Matrix | Qualitative | | Semi-Quantitative | | |
| --- | --- | --- | --- | --- | --- |
| | | Positive | Negative | Positive | Negative |
| K2 EDTA Plasma | Positive | 25 | 0 | 25 | 0 |
| | Negative | 0 | 25 | 0 | 25 |
| K3 EDTA plasma | Positive | 25 | 0 | 25 | 0 |
| | Negative | 0 | 25 | 0 | 25 |
| Lithium Heparin Plasma | Positive | 25 | 0 | 25 | 0 |
| | Negative | 0 | 25 | 0 | 25 |
| Sodium Citrate Plasma | Positive | 25 | 0 | 30 | 0 |
| | Negative | 0 | 25 | 0 | 25 |
| Potassium Oxalate Plasma | Positive | 25 | 0 | 25 | 0 |
| | Negative | 0 | 25 | 0 | 25 |
| Sodium Heparin Plasma | Positive | 25 | 0 | 25 | 0 |
| | Negative | 0 | 20 | 0 | 20 |
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C Clinical Studies:
1. Clinical Sensitivity:
Not applicable.
2. Clinical Specificity:
Not applicable.
3. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):
Not applicable.
D Clinical Cut-Off:
Not applicable.
E Expected Values/Reference Range:
Qualitative results
A sample that exhibits a change in absorbance (ΔA) value equal to or greater than the cutoff calibrator is considered positive. A sample that exhibits a change in absorbance (ΔA) value lower than the cutoff calibrator is considered negative.
Semiquantitative results
A rough estimate of drug concentration in the samples can be obtained by running a standard curve with all calibrators and measuring samples off the standard curve.
Immunoassays that produce only a single result in the presence of a class of drugs such as Tricyclic Antidepressants (TCAs) cannot accurately measure the concentration of each individual component. For a qualitative application, a positive result indicates only the presence of TCAs. For a semiquantitative application, the assay gives an approximate, cumulative concentration of TCAs.
VIII Proposed Labeling:
The labeling supports the finding of substantial equivalence for this device.
IX Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
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