← Product Code [LDP](/submissions/TX/subpart-d%E2%80%94clinical-toxicology-test-systems/LDP) · K180835

# SEKURE Acetaminophen L3K Assay (K180835)

_Sekisui Diagnostics P.E.I., Inc. · LDP · Feb 8, 2019 · Clinical Toxicology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/TX/subpart-d%E2%80%94clinical-toxicology-test-systems/LDP/K180835

## Device Facts

- **Applicant:** Sekisui Diagnostics P.E.I., Inc.
- **Product Code:** [LDP](/submissions/TX/subpart-d%E2%80%94clinical-toxicology-test-systems/LDP.md)
- **Decision Date:** Feb 8, 2019
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 862.3030
- **Device Class:** Class 2
- **Review Panel:** Clinical Toxicology

## Indications for Use

For the in vitro quantitative measurement of acetaminophen in serum, lithium heparin plasma and sodium heparin plasma. Measurement of acetaminophen is used in the diagnosis and treatment of acetaminophen overdose toxicity.

## Device Story

The SEKURE Acetaminophen L3K assay is an enzymatic, spectrophotometric in vitro diagnostic test. It utilizes an enzyme reagent containing acyl amidohydrolase to cleave the amide bond of acetaminophen, producing p-aminophenol. This product reacts with 2,5-dimethylphenol in the presence of manganese to form a chromophore. The resulting increase in absorbance at 605 nm is measured on open-system clinical chemistry analyzers (e.g., Hitachi 717) and is directly proportional to the acetaminophen concentration in the sample. The device is used in clinical laboratory settings by trained personnel. Results are provided to healthcare providers to assess acetaminophen levels, facilitating the diagnosis and management of overdose toxicity.

## Clinical Evidence

No clinical data. Bench testing only. Performance validated via precision (CLSI EP05-A3), LoB/LoD/LoQ (CLSI EP17-A2), linearity (CLSI EP06-A), and interference studies (CLSI EP07-A2). Method comparison against the predicate on 105 patient specimens showed a correlation coefficient of ≥ 0.999 and slope of 0.974-1.009, meeting acceptance criteria.

## Technological Characteristics

Quantitative colorimetric enzymatic assay. Reagents: Enzyme reagent (acyl amidohydrolase, MnCl2, sodium azide) and Color reagent (2,5-dimethylphenol, sodium carbonate buffer). Platform: Roche Hitachi 717 chemistry analyzer. Measuring range: 115–2500 μmol/L. Traceable to USP reference acetaminophen. Stability: 12-month shelf life.

## Regulatory Identification

An acetaminophen test system is a device intended to measure acetaminophen, an analgestic and fever reducing drug, in serum. Measurements obtained by this device are used in the diagnosis and treatment of acetaminophen overdose.

## Predicate Devices

- SEKURE Acetaminophen L3K Assay ([K081938](/device/K081938.md))

## Submission Summary (Full Text)

> This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com.
>
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY ASSAY ONLY TEMPLATE

A. 510(k) Number:
k180835

B. Purpose for Submission:
Modification of a previously cleared Acetaminophen assay (k081938), including a change in reagent formulation.

C. Measurand:
Acetaminophen

D. Type of Test:
Quantitative colorimetric assay

E. Applicant:
Sekisui Diagnostics PEI Inc.

F. Proprietary and Established Names:
SEKURE Acetaminophen L3K Assay

G. Regulatory Information:
|  Product Code | Classification | Regulation Section | Panel  |
| --- | --- | --- | --- |
|  LDP | II | 21 CFR 862.3030, Acetaminophen test system | 91- Toxicology  |

H. Intended Use:
1. Intended use(s):
See Indications for use below.

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2. Indication(s) for use:

For the in vitro quantitative measurement of acetaminophen in serum, lithium heparin plasma and sodium heparin plasma. Measurement of acetaminophen is used in the diagnosis and treatment of acetaminophen overdose toxicity.

3. Special conditions for use statement(s):

For prescription use only

4. Special instrument requirements:

Roche Hitachi 717 chemistry analyzer

I. Device Description:

The SEKURE Acetaminophen L3K assay consists of two reagents, an enzyme reagent and a color reagent, and a calibrator.

- Acetaminophen Enzyme Reagent (R1): A solution containing buffer (pH 8.6 at 25°C), 0.3 mmol/L MnCl₂·4H₂O, ≥ 0.9 KU/L Acyl Amidohydrolase (microbial), 50 mg/L sodium azide.
- Acetaminophen Color Reagent (R2): A solution containing 0.1 mol/L sodium carbonate buffer (pH 11.5 at 25°C), 31 mmol/L 2,5-dimethylphenol, stabilizer, preservative.
- Acetaminophen Calibrator: 1 x 5 mL of a solution containing buffer (pH 5.2 at 25°C), 151 μg/mL (1000 μmol/L) acetaminophen, preservatives.

J. Substantial Equivalence Information:

1. Predicate device name(s) and 510(k) numbers:

Acetaminophen L3K Assay, k081938

2. Comparison with predicate:

|  Similarities  |   |   |
| --- | --- | --- |
|  Feature | Predicate Device (k081938): Acetaminophen L3K Assay | Candidate Device: SEKURE Acetaminophen L3K Assay Assay  |
|  Intended Use | Intended for the in vitro quantitative measurement of acetaminophen in serum and plasma. Measurement of acetaminophen is used in the diagnosis and treatment of acetaminophen overdose toxicity. | Same  |

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|  Similarities  |   |   |
| --- | --- | --- |
|  Feature | Predicate Device (k081938): Acetaminophen L3K Assay | Candidate Device: SEKURE Acetaminophen L3K Assay Assay  |
|  Test Principle | Enzymatic and Spectrophotometric | Same  |
|  Platform | Hitachi 717 | Same  |
|  Differences  |   |   |
| --- | --- | --- |
|  Feature | Predicate Device (k081938): Acetaminophen L3K Assay | Candidate Device: SEKURE Acetaminophen L3K Assay Assay  |
|  Sample Types | Serum and lithium heparin plasma | Serum, lithium heparin plasma and sodium heparin plasma  |
|  Measuring interval | 4 to 2500 μmol/L (0.6 to 377.5 μg/mL) | 115 to 2500 μmol/L (17.4 to 377.5 μg/mL)  |

# K. Standard/Guidance Document Referenced (if applicable):

- CLSI EP05-A3- Evaluation of Precision Performance of Quantitative Measurement Methods
- CLSI EP06-A- Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach
- CLSI EP07-A2- Interference Testing in Clinical Chemistry
- CLSI EP17-A2- Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures
- CLSI EP09-A3- Method Comparison and Bias Estimation Using Patient Samples; Approved Guideline-Second Edition
- CLSI EP25-A- Evaluation of Stability of In Vitro Diagnostic Reagents

# L. Test Principle:

The enzyme, acyl amidohydrolase, cleaves the amide bond of the acetaminophen molecule, leaving p-aminophenol and acetate. The p-aminophenol is coupled with 2,5-dimethylphenol in the presence of manganese ions to form a colored compound, 4-(4-iminophenol)-2,5-dimethylcyclohexadiene-1-one. The increased absorbance at  $605\mathrm{nm}$  due to the formation of 4-(4-iminophenol)-2,5-dimethylcyclohexadiene-1-one is directly proportional to the concentration of acetaminophen in the sample.

# M. Performance Characteristics (if/when applicable):

All performance studies were conducted with the Roche Hitachi 717 clinical chemistry analyzer.

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# 1. Analytical performance:

# a. Precision/Reproducibility:

A precision study was performed using two unaltered patient serum samples, two spiked patient serum samples and three levels of controls, assayed in duplicate, twice a day, for 20 days, with daily calibration. Each sample was evaluated using six lots of Acetaminophen L3K Assay.

Repeatability:

|  Lot | Sample | N | Mean Acetaminophen (μmol/L) | Repeatability |   | Within Laboratory  |   |
| --- | --- | --- | --- | --- | --- | --- | --- |
|   |   |   |   |  SD (μmol/L) | %CV | SD (μmol/L) | %CV  |
|  1 | Control 1 | 80 | 68 | 1.8 | 2.7 | 2.5 | 3.8  |
|   |  Control 2 | 80 | 238 | 4.4 | 1.9 | 6.1 | 2.6  |
|   |  Control 3 | 80 | 764 | 13.4 | 1.8 | 14.3 | 1.9  |
|  2 | Unaltered P1 | 80 | 170.3 | 2.1 | 1.2 | 2.4 | 1.4  |
|   |  Unaltered P2 | 80 | 195.5 | 2.4 | 1.2 | 2.6 | 1.4  |
|   |  Spiked 1 | 80 | 1295.9 | 11.5 | 0.9 | 19.7 | 1.5  |
|   |  Spiked 2 | 80 | 2278.6 | 17.3 | 0.8 | 51.0 | 2.2  |
|  3 | Control 1 | 80 | 68 | 1.1 | 1.7 | 2.4 | 3.5  |
|   |  Control 2 | 80 | 238 | 3.9 | 1.7 | 5.8 | 2.4  |
|   |  Control 3 | 80 | 764 | 14.2 | 1.9 | 14.2 | 1.9  |
|  4 | Unaltered P1 | 80 | 169.5 | 1.5 | 0.9 | 2.1 | 1.2  |
|   |  Unaltered P2 | 80 | 195.4 | 2.6 | 1.3 | 2.6 | 1.3  |
|   |  Spiked 1 | 80 | 1294.3 | 12.8 | 1.0 | 21.4 | 1.7  |
|   |  Spiked 2 | 80 | 2281.5 | 15.9 | 0.7 | 52.3 | 2.3  |
|  5 | Control 1 | 80 | 68 | 1.4 | 2.0 | 2.4 | 3.5  |
|   |  Control 2 | 80 | 238 | 4.0 | 1.6 | 5.8 | 2.4  |
|   |  Control 3 | 80 | 764 | 13.6 | 1.7 | 14.2 | 1.8  |
|  6 | Unaltered P1 | 80 | 175.0 | 1.6 | 0.9 | 2.0 | 1.2  |
|   |  Unaltered P2 | 80 | 202.0 | 2.7 | 1.3 | 3.0 | 1.5  |
|   |  Spiked 1 | 80 | 1339.3 | 13.8 | 1.0 | 22.5 | 1.7  |
|   |  Spiked 2 | 80 | 2357.9 | 17.5 | 0.7 | 50.0 | 2.1  |

# b. Linearity/assay reportable range:

Linearity was conducted in a study using three lots of SEKURE Acetaminophen L3K reagent and two lots of calibrator. Nine samples from 100 to  $2700\mu \mathrm{mol} / \mathrm{L}$  acetaminophen were prepared. A high concentration stock was prepared from a stock acetaminophen standard of USP acetaminophen in pooled acetaminophen-free human serum. The high concentration stock was then diluted with an acetaminophen free sample to generate seven linearity samples. Expected concentrations were calculated based on the known value of the USP standard material values and the dilution factors. Samples were analyzed in quadruplicate. The mean and deviation of the

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measured mean from theoretical values were calculated.

|  Expected Acetaminophen (μmol/L) | Lot 1 |   | Lot 2 |   | Lot 3  |   |
| --- | --- | --- | --- | --- | --- | --- |
|   |  Observed (μmol/L) | Deviation (%) | Observed (μmol/L) | Deviation (%) | Observed (μmol/L) | Deviation (%)  |
|  100 | 98.8 | -1.2% | 99.3 | -0.7% | 101.3 | 1.3%  |
|  115 | 116.3 | 1.1% | 115.5 | 0.4% | 118.5 | 3.0%  |
|  125 | 125.3 | 0.2% | 124.5 | -0.4% | 128.8 | 3.0%  |
|  250 | 251.0 | 0.4% | 251.5 | 0.6% | 260.3 | 4.1%  |
|  500 | 489.5 | -2.1% | 493.0 | -1.4% | 509.8 | 2.0%  |
|  1000 | 1015.8 | 1.6% | 1022.8 | 2.3% | 1048.8 | 4.9%  |
|  2000 | 2018 | 0.9% | 2020.0 | 1.0% | 2079.5 | 4.0%  |
|  2500 | 2515 | 0.6% | 2501.3 | 0.0% | 2587.3 | 3.5%  |
|  2700 | 2690.3 | -0.4% | 2686.5 | -0.5% | 2784.5 | 3.1%  |

The linearity data met acceptance criteria and support a measuring range from 115 to  $2500\mu \mathrm{mol} / \mathrm{L}$  (17.4 to  $377.5~\mu \mathrm{g / mL}$ ).

c. Traceability, Stability, Expected values (controls, calibrators, or methods):

The SEKURE Acetaminophen Calibrator is traceable to USP grade reference acetaminophen material. Stability protocol and results are reviewed and found acceptable. Stability testing supports a shelf life of 12 months.

d. Detection limit:

Limit of Blank (LoB): LoB was evaluated according to CLSI EP17-A2 using three lots of SEKURE Acetaminophen L3K reagent on the Hitachi 717. Five blank samples were assayed over three operating days for a total of 60 replicates per sample. For each reagent lot, the LoB results were ranked from lowest to highest concentration, and the LoB was estimated to be the result equivalent to the concentration at the 95th percentile. The LoB was determined to be  $1.0\mu \mathrm{mol} / \mathrm{L}$ .

Limit of Detection (LoD): Five low level samples were evaluated using three lots of reagents over three operating days for a total of 60 replicates per sample. The LoD was calculated for each reagent lot by  $\mathrm{LoD} = \mathrm{LoB} + \mathrm{C_pSD_L}$ . This study yielded a LoD of  $2.4\mu \mathrm{mol / L}$ .

Limit of quantitation (LoQ): A set of six low-level samples was measured using three lots of reagents over five runs across three operating days for a total of 40 replicates per sample. The LoQ was calculated based on  $\%$  total error is  $< 25\%$ . The LoQ was determined to be  $8\mu \mathrm{mol} / \mathrm{L}$ .

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# e. Analytical specificity:

# i. Interference from endogenous substances/cross reactants

Interference studies were performed in accordance to CLSI EP07-A2. Four acetaminophen serum pools prepared from USP acetaminophen dissolved in patient serum pool (33  $\mu$ mol/L, 100  $\mu$ mol/L, 199  $\mu$ mol/L and 900  $\mu$ mol/L) were evaluated. Testing was conducted using three lots of Acetaminophen reagent and two lots of calibrator on the Hitachi 717. The potential interferents were added individually to aliquots of the serum specimen pools. Control samples contained corresponding concentrations of acetaminophen without potential interferents. Significant interference was evaluated using a significance criterion of greater than  $\pm 10\%$  or 8  $\mu$ mol/L from control. The highest concentrations of each substance that did not show significant interference with each acetaminophen concentration tested are shown in the table below.

|  Substance concentration Tested | Highest Tested Concentration with No Significant Interference | Acetaminophen Concentration  |
| --- | --- | --- |
|  Hemoglobin (0 - 1000 mg/dL) | 200 mg/dL (31 μmol/L) | 30 μmol/L (4.5 μg/mL)  |
|   |  200 mg/dL (31 μmol/L) | 93 μmol/L (14.0 μg/mL)  |
|   |  400 mg/dL (62 μmol/L) | 188 μmol/L (28.4 μg/mL)  |
|   |  1000 mg/dL (155 μmol/L) | 861 μmol/L (130 μg/mL)  |
|  Conjugated Bilirubin (0 - 40 mg/dL) | 2 mg/dL (23.7 μmol/L) | 31 μmol/L (4.7 μg/mL)  |
|   |  2 mg/dL (23.7 μmol/L) | 98 μmol/L (14.8 μg/mL)  |
|   |  32 mg/dL (364 μmol/L) | 115 μmol/L (17.4 μg/mL)  |
|   |  40 mg/dL (475 μmol/L) | 200 μmol/L (30.2 μg/mL)  |
|   |  40 mg/dL (475 μmol/L) | 957 μmol/L (144 μg/mL)  |
|  Unconjugated Bilirubin (0 - 40 mg/dL) | 2 mg/dL (34.2 μmol/L) | 33 μmol/L (5.0 μg/mL)  |
|   |  4 mg/dL (68 μmol/L) | 98 μmol/L (14.8 μg/mL)  |
|   |  32 mg/dL (547 μmol/L) | 115 μmol/L (17.4 μg/mL)  |
|   |  24 mg/dL (410 μmol/L) | 200 μmol/L (30.2 μg/mL)  |
|   |  40 mg/dL (475 μmol/L) | 958 μmol/L (144 μg/mL)  |
|  Ascorbic Acid (0 - 3000 μg/dL) | 3000 μg/dL (170 μmol/L) | 30 μmol/L (4.5 μg/mL)  |
|   |  3000 μg/dL (170 μmol/L) | 107 μmol/L (16.2 μg/mL)  |
|   |  3000 μg/dL (170 μmol/L) | 215 μmol/L (32.5 μg/mL)  |
|   |  3000 μg/dL (170 μmol/L) | 946 μmol/L (142.8 μg/mL)  |
|  N-Acetylcysteine (0 - 2500 mg/L) | 1500 mg/L | 30 μmol/L (4.5 μg/mL)  |
|   |  1500 mg/L | 110 μmol/L (16.6 μg/mL)  |
|   |  1500 mg/L | 215 μmol/L (32.5 μg/mL)  |
|   |  1500 mg/L | 922 μmol/L (139.2 μg/mL)  |
|  Intralipid (0 - 1000 mg/dL) | 600 mg/dL [1800 mg/dL (20 mmol/L) Simulated Triglycerides] | 32 μmol/L (4.8 μg/mL)  |
|   |  1000 mg/dL [3000 mg/dL (34 mmol/L) Simulated | 100 μmol/L (15.1 μg/mL)  |

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|  Substance concentration Tested | Highest Tested Concentration with No Significant Interference | Acetaminophen Concentration  |
| --- | --- | --- |
|   | Triglycerides] |   |
|   |  1000 mg/dL [3000 mg/dL (34 mmol/L) Simulated Triglycerides] | 203 μmol/L (30.7 μg/mL)  |
|   |  1000 mg/dL [3000 mg/dL (34 mmol/L) Simulated Triglycerides] | 898 μmol/L (135.6 μg/mL)  |

Interference from common drugs was also examined. A total of 15 commonly used drugs were examined for potential interferences. Testing was performed with serum sample pools at four levels of acetaminophen (33, 100, 199, and 900 μmol/L).

Recoveries of acetaminophen were within the sponsor’s acceptance criteria of greater than ±10% or 8 μmol/L from control. The highest concentrations of common drugs shown not to interfere with the assay are provided in the table below.

|  Substance Tested | Concentration with No Significant Interference  |
| --- | --- |
|  Theophylline | 222 μmol/L  |
|  Phenylbutazone | 2.89 mmol/L  |
|  Ibuprofen | 2425 μmol/L  |
|  Imipramine | 2.5 μmol/L  |
|  Acetylsalicylic Acid | 6.51 mmol/L  |
|  Levodopa | 25.3 μmol/L  |
|  Ampicillin | 152 μmol/L  |
|  Doxycycline | 67.5 μmol/L  |
|  Amitriptyline | 3.61 μmol/L  |
|  Metronidazole | 701 μmol/L  |
|  Cefoxitin | 1546 μmol/L  |
|  Cyclosporine | 10.0 μmol/L  |
|  Methyldopa | 71 μmol/L  |
|  Rifampicin | 78.1 μmol/L  |
|  Salicylate | 4.34 mmol/L  |

f. Assay cut-off:

Not applicable.

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2. Comparison studies:

a. Method comparison with predicate device:

A method comparison test was conducted on the Roche Hitachi 717 analyzer using three lots of SEKURE Acetaminophen L3K reagent, as compared to one lot of the predicate Acetaminophen L3K reagent. 105 samples were tested in singlicate. The samples tested ranged from 116 to 2447 µmol/L (17.5 -369.4 µg/mL). Deming regression analysis resulted in a slope of 0.974, a y-intercept of 4.7 µmol/L, and a correlation coefficient of 0.9999. Passing-Bablok regression analysis resulted in a slope of 0.975, a y-intercept of 2.3 µmol/L, and a correlation coefficient of 0.9999.

b. Matrix comparison:

Matrix comparison studies were performed for Serum (with gel in plastic, SST), EDTA, Lithium heparin (with gel in plastic, PST), Lithium heparin (without gel in plastic), Lithium heparin (Barricor tube), Sodium heparin (without gel in plastic) vs serum (without gel in plastic). A set of fifty matched sample sets were tested and percent recovery was determined. All percent recoveries were within ± 10%.

|   | Sample Range | Slope |   | Correlation Coefficient  |
| --- | --- | --- | --- | --- |
|   |   |  Result Deming | Passing-Bablok | Result  |
|  SST | 115 – 2322 µmol/L | 1.012 | 1.007 | 1.000  |
|  EDTA |   | 0.303 | 0.303 | 0.988  |
|  Lithium Heparin |   | 1.015 | 1.012 | 1.000  |
|  PST |   | 1.009 | 1.000 | 1.000  |
|  Sodium Heparin |   | 1.012 | 1.006 | 1.000  |
|  Barricor |   | 1.005 | 1.000 | 1.000  |

3. Clinical studies:

a. Clinical Sensitivity:

Not applicable.

b. Clinical specificity:

Not applicable.

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c. Other clinical supportive data (when a. and b. are not applicable):

Not applicable.

4. Clinical cut-off:

Not applicable.

5. Expected values/Reference range:

Reference range were cited from the following literatures: Tietz Textbook of Clinical Chemistry, Second Edition, pp 1168, 2212, W.B. Saunders Company, Philadelphia (1994)

Therapeutic concentration: 10-30 µg/mL (66-199 µmol/L)

Toxic concentration: > 200 µg/mL (1324 µmol/L)

These values are suggested guidelines. It is recommended that each laboratory establish its own expected range.

N. Proposed Labeling:

The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

O. Conclusion:

The submitted information in this premarket notification is complete and supports a substantial equivalence decision.

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**Source:** [https://fda.innolitics.com/submissions/TX/subpart-d%E2%80%94clinical-toxicology-test-systems/LDP/K180835](https://fda.innolitics.com/submissions/TX/subpart-d%E2%80%94clinical-toxicology-test-systems/LDP/K180835)

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