DIAZYME HOMOCYSTEINE ASSAY BUFFER BASED CALIBRATORS
Device Facts
| Record ID | K102638 |
|---|---|
| Device Name | DIAZYME HOMOCYSTEINE ASSAY BUFFER BASED CALIBRATORS |
| Applicant | Diazyme Laboratories |
| Product Code | JIT · Clinical Chemistry |
| Decision Date | Nov 30, 2010 |
| Decision | SESE |
| Submission Type | Abbreviated |
| Regulation | 21 CFR 862.1150 |
| Device Class | Class 2 |
Intended Use
Diazyme Homocysteine Assay Buffer Based Calibrators are intended for use with the Diazyme Homocysteine Assay Kit only. The calibrators are used to generate a calibration curve to be used in the calculation of homocysteine concentrations in unknown serum and plasma samples. For in vitro diagnostic use only.
Device Story
Diazyme Homocysteine Assay Buffer Based Calibrators are liquid, ready-to-use calibrators containing L-homocystine, stabilizers, and preservatives. Used in clinical chemistry laboratories with Hitachi 917 or Olympus AU systems. The device functions by generating a calibration curve for the Diazyme Homocysteine Assay Kit, allowing the calculation of homocysteine concentrations in unknown patient serum and plasma samples. The healthcare provider uses the resulting concentration values to assess patient homocysteine levels. The device benefits patients by ensuring accurate, standardized quantification of homocysteine, which is clinically relevant for assessing cardiovascular and metabolic health.
Clinical Evidence
No clinical data. Bench testing only. Performance validated via precision studies (CV 0.65-4.35%), linearity studies (R² ≥ 0.9878), and method comparison against predicate (correlation coefficients 0.9927-0.9971). Traceability established using NIST SRM 1995. Interference testing confirmed <10% deviation for common substances (e.g., cysteine, glutathione, bilirubin, triglycerides).
Technological Characteristics
Ready-to-use liquid calibrator; contains L-homocysteine, stabilizers, and preservatives in an aqueous buffered solution. Designed for use with Hitachi 917 and Olympus AU clinical chemistry analyzers. Stability validated for 24 months at 2-8°C. Complies with CLSI guidelines EP5-A2, EP9-A2, EP6-A, and EP7-A2.
Indications for Use
Indicated for use with the Diazyme Homocysteine Assay Kit to calculate homocysteine concentrations in human serum and plasma samples. For prescription use only.
Regulatory Classification
Identification
A calibrator is a device intended for medical purposes for use in a test system to establish points of reference that are used in the determination of values in the measurement of substances in human specimens. (See also § 862.2 in this part.)
Special Controls
*Classification.* Class II (special controls). 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.
Predicate Devices
- Diazyme Homocysteine Calibrators (k042448)
Related Devices
- K982003 — DS30 HCY HOMOCYSTEINE ASSAY KIT · Drew Scientific , Ltd. · Feb 11, 1999
- K071971 — DIAZYME HOMOCYSTEINE 2 REAGENT ENZYMATIC ASSAY KIT, AND CALIBRATORS, MODEL(S) DZXXXA, DZXXXA-CAL · Diazyme Laboratories · Sep 17, 2007
- K042448 — DIAZYME HOMOCYSTEINE ENZYMATIC ASSAY KIT · General Atomics · Oct 29, 2004
- K011689 — HOMOGENEOUS ENZYMIC HOMOCYSTEINE REAGENT · Catch, Inc. · Jul 25, 2001
Submission Summary (Full Text)
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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
DEVICE ONLY TEMPLATE
A. 510(k) Number:
k102638
B. Purpose for Submission:
New device
C. Measurand:
Calibrator for Homeocysteine Assay
D. Type of Test:
Not Applicable
E. Applicant:
Diazyme Laboratories
F. Proprietary and Established Names:
Diazyme Homocysteine Assay Buffer Based Calibrators
G. Regulatory Information:
1. Regulation section:
21 CFR §862.1150, Calibrator
2. Classification:
Class II
3. Product code:
JIS – Calibrator, Primary
4. Panel:
Clinical Chemistry (75)
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H. Intended Use:
1. Intended use(s):
See Indications for Use below.
2. Indications(s) for use:
Diazyme Homocysteine Assay Buffer Based Calibrators are intended for use with the Diazyme Homocysteine Assay Kit only. The calibrators are used to generate a calibration curve to be used in the calculation of homocysteine concentrations in unknown serum and plasma samples. For in vitro diagnostic use only.
3. Special conditions for use statement(s):
For prescription use only
4. Special instrument requirements:
Hitachi 917 and Olympus AU Systems
I. Device Description:
Diazyme Homocysteine Assay Buffer Based Calibrators are for use with the Diazyme Homocysteine Assay Kits to generate a calibration curve to calculate the concentration of homocysteine in unknown serum and plasma samples. It is supplied as a ready to use liquid with the active ingredient L-homocysteine, stabilizers and preservatives.
J. Substantial Equivalence Information:
1. Predicate device name(s):
Diazyme Homocysteine Calibrators
2. Predicate 510(k) number(s):
k042448
3. Comparison with predicate:
| Reagent Similarities and Differences | | |
| --- | --- | --- |
| | Candidate Device
Diazyme Homocysteine Assay
Buffer Based Calibrators | Predicate Device
Diazyme Homocysteine
Calibrators (k042448) |
| Intended Use | Diazyme Homocysteine Assay | Diazyme Homocysteine Assay |
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| Reagent Similarities and Differences | | |
| --- | --- | --- |
| | Candidate Device
Diazyme Homocysteine Assay
Buffer Based Calibrators | Predicate Device
Diazyme Homocysteine
Calibrators (k042448) |
| | Calibrator set is intended for use with the Diazyme Homocysteine Assay Kit only. The calibrators are used to generate a calibration curve to be used in the calculation of homocysteine concentrations in unknown serum and plasma samples. For in vitro diagnostic use only. | calibrator set is intended for use with the Diazyme Homocysteine Assay Kit only. For in vitro diagnostic use only. |
| Specimen Matrix | Human serum and plasma | same |
| Calibrator Ingredients | Human serum, saline preservatives and active ingredient L-homocystine | Aqueous buffered solution, preservative, and active ingredient L-homocystine |
| Linear Range | Up to 50 μmol/L for both 2-reagent and 3-reagent HCY | same |
| Precision | 3-reagent HCY, 2-point calibrators on Hitachi 917 Intra: 0.82-1.89%
3-reagent HCY, 5-point calibrators on Hitachi 917, Intra: 0.65-3.66%
2-reagent HCY 2 and 3-point calibrators on Olympus AU400 Intra: 1.54-4.35% | 3-reagent HCY: Within: 1.8-3.0% |
| Accuracy | 3-reagent HCY, 2-point calibrators on Hitachi 917:
Correlation Coefficient: 0.9961
y=1.0134x + 0.8266
3-reagent HCY, 5-point calibrators on Hitachi 917:
Correlation Coefficient: 0.9971
y=0.9357x + 0.5186
2-reagent HCY 2 and 3-point calibrators on Olympus AU400
Correlation Coefficient: 0.9927
y=1.0167x – 0.0535
2-reagent HCY 2 and 5-point calibrators on Olympus AU400
Correlation Coefficient: 0.997 | 3-reagent HCY:
Correlation Coefficient: 0.976
y=0.98x + 0.87 |
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| Reagent Similarities and Differences | | |
| --- | --- | --- |
| | Candidate Device
Diazyme Homocysteine Assay
Buffer Based Calibrators | Predicate Device
Diazyme Homocysteine
Calibrators (k042448) |
| | y=0.9601x – 0.0345 | |
| Linear Range | 3-reagent HCY:
Up to 50 μmol/L
2-reagent HCY:
Up to 50 μmol/L | 3-reagent HCY:
Up to 50 μmol/L |
K. Standard/ Guidance Document Referenced (if applicable):
- Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline - Second Edition - (CLSI EP5-A2).
- Method Comparison and Bias Estimation Using Patient Samples; Approved Guideline-Second Edition - (CLSI EP9-A2).
- Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach; Approved Guideline - (CLSI EP6-A).
- Interference Testing in Clinical Chemistry; Approved Guideline-Second Edition – (CLSI EP7-A2)
L. Test Principle:
Not applicable
M. Performance Characteristics (if/when applicable):
1. Analytical performance:
a. Precision/Reproducibility:
The sponsor performed intra precision studies with four serum based samples using the Homocysteine (HCY) Enzymatic Assay. The assay was performed within one day with 12 replicates. The acceptance criterion is precision CV ≤ 5%. The results are as follows:
| Sample Type | Reagent | N | Instrument | Calibrator | Replicates | %CV |
| --- | --- | --- | --- | --- | --- | --- |
| Serum | 3-Reagent HCY | 4 | Hitachi 917 | 5-point Calibrator | 12 | 0.65-3.66% |
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| Serum | 3-Reagent HCY | 4 | Hitachi 917 | 2-point calibrator | 12 | 0.82-1.89% |
| --- | --- | --- | --- | --- | --- | --- |
| Serum | 2-Reagent HCY | 4 | Olympus AU 400 | 3-point calibrator | 21 | 1.83-4.35% |
| Serum | 2-Reagent HCY | 4 | Olympus AU 400 | 5-point calibrator | 21 | 1.53-2.76% |
## b. Linearity/assay reportable range:
A linearity study was performed based on the CLSI EP6-A guideline. Eleven levels of the linearity set were prepared by diluting a serum sample containing 50 µM HCY with saline. A slope of 1.0 ± 0.1 and R² of ≥ 0.95 for expected versus obtained samples were the acceptance criteria. Results are summarized below:
| Sample Type | Analyzer | Instrument | Calibrator | Slope | y-intercept | R² |
| --- | --- | --- | --- | --- | --- | --- |
| Serum | 2-Reagent HCY | Olympus AU 400 | 3point calibrator | 0.9978 | 0.7109 | .9957 |
| Serum | 2-Reagent HCY | Olympus AU 400 | 5-point calibrator | 1.0438 | 0.2341 | .9982 |
| Serum | 3-Reagent HCY | Hitachi 917 | 2-point calibrator | 0.9589 | 0.5811 | .9878 |
| Serum | 3-Reagent HCY | Hitachi 917 | 5-point calibrator | 1.048 | 0.2373 | .9967 |
## c. Traceability, Stability, Expected values (controls, calibrators, or methods):
### Traceability:
The calibrator value assignment includes testing with NIST Standard Reference Material 1995. The HCY calibrator is prepared by spiking a calculated amount of L-homecystine stock solution to aqueous solution containing preservative to the target homocysteine concentration. The manufacturer then uses selected measurement methods to test and release the production calibrator on specified analyzer. The production calibrator with the final values is assigned and then used to test library samples, proficiency library samples and higher order trueness NIST SRM1955 serum controls.
### Stability:
The calibrators are tested for shelf life protections with an accelerated stability protocol. The sponsor places the calibrators at each level in a 37°C incubator and at
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the indicated time, test them with the current Diazyme HCY reagent and calibrators for HCY recovery. The acceptance criteria are that the calibrator should be stable for at least 12 months based on the stress test performance (7 days at 37°C and >1 month at 25°C) and the recovery should meet or exceed 90% of initial value. The study was performed on an Olympus AU400 using 2- HCY reagent and 5-point buffered calibrators. The calibrator did not change more than 10% after 14 days of 37°C stress, 60 days of 25°C in open or closed vial accelerated stability tests. The sponsor states that the calibrators are stable for 24 months when stored at 2-8°C based on Arrhenius theory stress models and real-time studies are on-going.
## Expected Values:
The sponsor tested the NIST SRM1955 Controls for recovery. They had a within control range acceptance criteria of 15% or 2 μmol/L for NIST SRM1955 controls.
2-Reagent HCY: Results for Olympus AU400 using 2-reagent HCY reagent and 3-point buffer based calibrator
| Sample | Value | Recovery | % Recovery |
| --- | --- | --- | --- |
| NIST 1 | 3.98 | 3.84 | 96.48% |
| NIST 2 | 8.85 | 9.23 | 10.29% |
| NIST 3 | 17.7 | 16.32 | 9.20% |
2-Reagent HCY: Results for Olympus AU400 using 2-reagent HCY reagent and 5-point buffer based calibrator
| Sample | Value | Recovery | % Recovery |
| --- | --- | --- | --- |
| NIST 1 | 3.98 | 3.91 | 98.24% |
| NIST 2 | 8.85 | 8.05 | 90.96% |
| NIST 3 | 17.7 | 16.14 | 91.19% |
3-Reagent HCY: Results for Hitachi 917 using 3-reagent HCY reagent and 2-point buffer based calibrator
| Sample | Value | Recovery | % Recovery |
| --- | --- | --- | --- |
| NIST 1 | 3.98 | 3.64 | 91.46% |
| NIST 2 | 8.85 | 9.905 | 111.92% |
| NIST 3 | 17.7 | 18.835 | 106.41% |
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3-Reagent HCY: Results for Hitachi 917 using 3-reagent HCY reagent and 5-point buffer based calibrator
| Sample | Value | Recovery | % Recovery |
| --- | --- | --- | --- |
| NIST 1 | 3.98 | 3.69 | 92.71% |
| NIST 2 | 8.85 | 8.74 | 98.76% |
| NIST 3 | 17.7 | 17.87 | 100.96% |
d. Detection limit:
Not applicable
e. Analytical specificity:
The sponsor performed interference studies by testing serum samples at 12 and 29 $\mu$ M HCY spiked with interference substances to verify tolerance limits. Potential cross-reactive compounds (see table below) were added and tested using the Diazyme HCY Enzymatic Assay. The following substances present in the serum produced less than $10\%$ deviation when tested at the stated concentrations.
| Potential Cross-Reactive Agent | Spiking Concentration |
| --- | --- |
| Cysteine | 1000 μM |
| Glutathione | 500 μM |
| Cystathionine | 100 μM |
| Hemoglobin | 500 mg/dL |
| Unconjugated Bilirubin | 40 mg/dL |
| Conjugated Bilirubin | 40 mg/dL |
| Ascorbic Acid | 100mM |
| Triglyceride | 500 mg/dL |
f. Assay cut-off:
Not Applicable
2. Comparison studies:
a. Method comparison with predicate device:
Accuracy
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The sponsor performed accuracy studies with forty serum based samples using the Homocysteine (HCY) Enzymatic Assay and comparing the buffer based calibrators with the current serum based calibrators. The assay was performed within one day with 12 replicates and all samples met the acceptance criteria. The results were as follows:
| Sample Type | Analyzer | N | Instrument | Calibrator | Slope | R² |
| --- | --- | --- | --- | --- | --- | --- |
| Serum | 2-Reagent HCY | 40 | Olympus AU 400 | 3-point calibrator | 1.0167 | .9927 |
| Serum | 2-Reagent HCY | 40 | Olympus AU 400 | 5-point calibrator | 0.9601 | .997 |
| Serum | 3-Reagent HCY | 40 | Hitachi 917 | 2-point calibrator | 1.0134 | .9961 |
| Serum | 3-Reagent HCy | 40 | Hitachi 917 | 5-point calibrator | 0.9357 | .9971 |
b. Matrix comparison:
Not applicable.
3. Clinical studies:
a. Clinical Sensitivity:
Not Applicable
b. Clinical specificity:
Not Applicable
c. Other clinical supportive data (when a. and b. are not applicable):
Not Applicable
4. Clinical cut-off:
Not Applicable
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5. Expected values/Reference range
Not Applicable
**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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