DIAZYME HSCRP POC TEST KIT
Device Facts
| Record ID | K121558 |
|---|---|
| Device Name | DIAZYME HSCRP POC TEST KIT |
| Applicant | Diazyme Laboratories |
| Product Code | DCK · Immunology |
| Decision Date | Sep 21, 2012 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 866.5270 |
| Device Class | Class 2 |
| Attributes | Real-World Evidence |
Real-World Evidence
| Submission | Device | Sponsor | RWD Sources | RWE Use Summary | Key Tags |
|---|---|---|---|---|---|
| K121558 · Sep 21, 2012 | DIAZYME HSCRP POC TEST KIT | Diazyme Laboratories | Physician Office Laboratory (POL) clinical samples | Clinical samples from three POL sites were used to perform an external method comparison and precision evaluation to demonstrate substantial equivalence to the predicate device. | Method comparison; POL sites; Clinical samples |
Clinical Evidence
| Study Design | Population | Comparator | Key Endpoints |
|---|---|---|---|
| External precision evaluation at point-of-care sites; Follow-up/Duration: 5 days | Whole blood samples; Sample Size: 6 whole blood samples (2 per site); Number of Sites: 3 | Not applicable for this study | Within-run and total precision (CV%) |
| Method comparison study | 120 paired human whole blood-serum samples; Sample Size: 116 (after exclusions); Number of Sites: 3 | Hitachi 917 analyzer (predicate k103557) | Slope, intercept, and correlation coefficient |
Indications for Use
The Diazyme high sensitivity C-reactive protein (hsCRP) POC Test Kit is for the in vitro quantitative determination of C-reactive protein (CRP) in human venous whole blood on SMART analyzers. Measurement of CRP is of use for the detection and evaluation of inflammatory disorders and associated diseases, infection and tissue injury. For in vitro diagnostic use only. The Diazyme hsCRP POC control set is intended for use as quality controls for the Diazyme hsCRP POC Test Kit. For in vitro diagnostic use only.
Device Story
The Diazyme hsCRP POC Test Kit is a point-of-care diagnostic system used in clinical settings (e.g., physician offices) by healthcare professionals (nurses, assistants) to measure CRP levels in human venous whole blood. The system utilizes a latex-enhanced immunoturbidimetric assay; patient samples are mixed with anti-human CRP rabbit polyclonal antibody-coated latex particles. Antigen-antibody reactions cause agglutination, which is measured as an absorbance change at 700 nm on the Diazyme SMART analyzer. The analyzer calculates CRP concentration using a lot-specific calibration curve stored on an RFID card provided with the kit. Results assist clinicians in detecting and evaluating inflammatory disorders, infections, and tissue injuries. The device provides quantitative data to support clinical decision-making regarding patient inflammatory status.
Clinical Evidence
Bench testing only. Precision evaluated per CLSI EP5-A (internal and external POL sites); total imprecision CVs ranged from 2.12% to 8.17%. Linearity established from 0.47 mg/L to 23.0 mg/L. Analytical specificity confirmed against common endogenous/exogenous interferents. Method comparison (n=116 paired samples) against predicate (K103557) showed slope 0.9712, intercept -0.0870, and r=0.9836. Reference range verified in 150 healthy adults.
Technological Characteristics
Latex-enhanced immunoturbidimetric assay. Reagents: TrisCl buffer and anti-human CRP rabbit polyclonal antibody-coated latex particles (<0.5%). Detection: 700 nm absorbance. Calibration: Lot-specific RFID card. Specimen: Venous whole blood. Platform: Diazyme SMART analyzer (k092911).
Indications for Use
Indicated for in vitro quantitative determination of CRP in human venous whole blood to detect and evaluate inflammatory disorders, infection, and tissue injury. Intended for prescription use.
Regulatory Classification
Identification
A C-reactive protein immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the C-reactive protein in serum and other body fluids. Measurement of C-reactive protein aids in evaluation of the amount of injury to body tissues.
Predicate Devices
- Diazyme hsCRP Assay (K103557)
Submission Summary (Full Text)
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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
ASSAY ONLY TEMPLATE
A. 510(k) Number:
k121558
B. Purpose for Submission:
New assay
C. Measurand:
C-reactive protein
D. Type of Test:
Quantitative Immunoturbidimetric
E. Applicant:
Diazyme Laboratories
F. Proprietary and Established Names:
Diazyme hsCRP POC Test Kit
Diazyme hsCRP POC control set
G. Regulatory Information:
1. Regulation section:
C-reactive protein immunological test system 21 CFR 866.5270
2. Classification:
Class II (assay), Class I, reserved (control materials)
3. Product code:
DCK (assay), JJX (control materials)
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4. Panel:
Immunology (82), Clinical Chemistry (75)
## H. Intended Use:
1. Intended use(s):
See indications for use.
2. Indication(s) for use:
The Diazyme high sensitivity C-reactive protein (hsCRP) POC Test Kit is for the in vitro quantitative determination of C-reactive protein (CRP) in human venous whole blood on SMART analyzers. Measurement of CRP is of use for the detection and evaluation of inflammatory disorders and associated diseases, infection and tissue injury. For in vitro diagnostic use only.
The Diazyme hsCRP POC control set is intended for use as quality controls for the Diazyme hsCRP POC Test Kit. For in vitro diagnostic use only.
3. Special conditions for use statement(s):
For prescription use only.
4. Special instrument requirements:
The Diazyme SMART analyzer (k092911)
## I. Device Description:
The Diazyme hsCRP POC Test Kit system consists of the following:
| Kit components |
| --- |
| Reagent 1
40 DRS cuvette (prefilled)
• 100 mM TrisCl buffer |
| Reagent 2
40 DRS caps (prefilled)
• Suspension of anti-human CRP rabbit polyclonal antibody coated latex particles (< 0.5%). |
| |
| Calibrator |
| 1 x preprogrammed lot specific RFID card in each kit |
| |
| Control Set |
| 1 x 1.0 mL Control 1 |
| 1 x 1.0 mL Control 2 |
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J. Substantial Equivalence Information:
1. Predicate device name(s):
Diazyme high sensitivity C-reactive protein (hsCRP) assay; Diazyme high sensitivity C-reactive protein (hsCRP) control kit
2. Predicate 510(k) number(s):
k103557
3. Comparison with predicate:
| Feature | Predicate k103557 | Candidate device |
| --- | --- | --- |
| Intended use/Indications for use | Assay: for the in vitro quantitative determination of C-reactive protein (CRP). Measurement of CRP is of use for the detection and evaluation of inflammatory disorders and associated diseases, infection and tissue injury. For in vitro diagnostic use only.
Control: the control set is intended for use as quality controls for hsCRP. For in vitro diagnostic use only. | Same |
| Principle | Based on a latex enhanced immunoturbidimetric assay. When an antigen-antibody reaction occurs between CRP in a sample and anti-CRP which has been sensitized to latex particles, agglutination results. This agglutination is detected as an absorbance change with the magnitude of the change being proportional to the quantity of CRP in the sample. | Same |
| --- | --- | --- |
| Detection | 570 nm | 700 nm |
| --- | --- | --- |
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| wavelength | | |
| --- | --- | --- |
| Assay range | 0.2-20 mg/L | 0.47 – 23.00 mg/L |
| --- | --- | --- |
| Methodology | Latex enhanced immunoturbidimetric method | Same |
| --- | --- | --- |
| Antibodies | Latex particles coated with goat anti-human CRP polyclonal antibodies | Same |
| --- | --- | --- |
| Specimen | 5μL Human serum or plasma. | 20 μL Human whole blood. |
| --- | --- | --- |
| Calibrator and Controls | Calibrator kit, quality control kit | RFID calibration card, quality control kit |
| --- | --- | --- |
## K. Standard/Guidance Document Referenced (if applicable):
- CLSI Guideline EP5-A2: Evaluation of Precision Performance of Quantitative Measurement Methods
- CLSI Guideline EP9-A2: Method Comparison and Bias Estimation Using Patient Samples
- CLSI Guideline EP7-A2: Interference Testing in Clinical Chemistry
## L. Test Principle:
Diazyme’s hsCRP POC Test Kit is based on a latex enhanced immunoturbidimetric assay on Diazyme’s SMART analyzer. (The SMART Analyzer was cleared under k092911). When an antigen-antibody reaction occurs between CRP in a sample and anti-CRP which has been sensitized to latex particles agglutination results. This agglutination is detected as an absorbance change (700 nm), with the magnitude of the change being proportional to the quantity of CRP in the sample. The instrument calculates the CRP concentration of patient specimen by use of a lot specific calibration curve that is stored in an RFID card provided with each hsCRP POC kit. The RFID card is inserted in the SMART analyzer and is needed for every single run.
## M. Performance Characteristics (if/when applicable):
1. Analytical performance:
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# a. Precision/Reproducibility:
The precision of the Diazyme hsCRP POC Test Kit was evaluated according to Clinical and Laboratory Standards Institute (CLSI) EP5-A guideline with the following modifications: In the study, whole blood specimens containing $0.80\mathrm{mg / L}$ , $3.25\mathrm{mg / L}$ , and $12.50\mathrm{mg / L}$ CRP were tested in 4 runs per day on three different SMART Analyzers. The results are listed below.
# (1) Internal precision study performed at Diazyme Laboratories
The mean value (Mean), standard deviation, within run imprecision and total imprecision $\mathrm{CV}$ mg/L are calculated and summarized in the following tables:
Within Run precision
| Total data points | Whole blood 1 0.80 mg/L hs-CRP 40 | Whole blood 2 3.25 mg/L hs-CRP 40 | Whole blood 3 12.50 mg/L hs-CRP 40 |
| --- | --- | --- | --- |
| Mean (mg/L) | 0.813 | 3.186 | 12.560 |
| SD (mg/L) | 0.0782 | 0.0901 | 0.2247 |
| %CV | 9.62% | 2.83% | 1.79% |
Within Laboratory:
| Total data points | Whole blood 1 1.00 mg/L hs-CRP 40 | Whole blood2 3.25 mg/L hs-CRP 40 | Whole blood 3 12.50 mg/L hs-CRP 40 |
| --- | --- | --- | --- |
| Mean (mg/L) | 0.813 | 3.186 | 12.560 |
| SD (mg/L) | 0.0664 | 0.0984 | 0.2667 |
| %CV | 8.17% | 3.09% | 2.12% |
# 2) External precision study performed at POL sites
Precision was evaluated at three (3) physician office laboratories (POL) by intended users such as nurses and office assistants. Six (6) whole blood samples containing C Reactive Protein levels ranging from low to high were tested. At each site, 2 whole blood samples were tested. Each sample was run 4 times per day for 5 days using three SMART Analyzers.
Within run precision:
| | Site 1 | | Site 2 | | Site 3 | |
| --- | --- | --- | --- | --- | --- | --- |
| | Whole blood 1 | Whole blood 2 | Whole blood 3 | Whole blood 4 | Whole blood 5 | Whole blood 6 |
| No. of | 20 | 20 | 20 | 20 | 20 | 20 |
| Mean (mg/L) | 0.813 | 3.186 | 12.560 | 0.813 | 3.186 | 12.560 |
| SD (mg/L) | 0.0664 | 0.0984 | 0.2667 | 0.0664 | 0.0984 | 0.2667 |
| %CV | 8.17% | 3.09% | 2.12% | 0.0000 | 0.0000 | 0.0000 |
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| Points | | | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| Mean (mg/L) | 0.798 | 4.796 | 0.758 | 17.796 | 7.780 | 18.725 |
| SD (mg/L) | 0.0372 | 0.3369 | 0.0684 | 0.7447 | 0.4225 | 0.9409 |
| CV | 4.67% | 7.02% | 9.04% | 4.18% | 5.43% | 5.02% |
Within-laboratory precision:
| | Site 1 | | Site 2 | | Site 3 | |
| --- | --- | --- | --- | --- | --- | --- |
| | Whole blood 1 | Whole blood 2 | Whole blood 3 | Whole blood 4 | Whole blood 5 | Whole blood 6 |
| No. of Points | 20 | 20 | 20 | 20 | 20 | 20 |
| Mean (mg/L) | 0.798 | 4.796 | 0.758 | 17.796 | 7.780 | 18.752 |
| SD (mg/L) | 0.0684 | 0.3674 | 0.0616 | 0.7153 | 0.4082 | 0.8951 |
| CV | 8.58% | 7.37% | 8.13% | 4.02% | 5.24% | 4.78% |
b. Linearity/assay reportable range:
A set of eleven levels of linearity materials were prepared by diluting a whole blood sample containing 28.0 mg/L of C Reactive Protein (CRP) with saline according to Clinical and Laboratory Standards Institute EP6-A and were tested with the Diazyme C Reactive Protein POC Test in triplicate on the SMART Analyzer. Testing included samples with concentrations near the LoQ. Conclusion: Linearity data and the LOQ data support Analytical Measuring Range (AMR) of 0.47 mg/L to 23.00 mg/L.
The regression equation yielded slope of 0.996; intercept of -0.0065 and R² of 0.9999.
The package insert recommends diluting samples with CRP > 23.0 mg/L 1:1 with saline. To demonstrate validity, 3 whole blood samples (spiked) containing CRP near the upper detection limit of 26.0 mg/L CRP were diluted 1:1 with saline and tested on the SMART analyzer. Recoveries based on dilutions were all within 95% of the expected concentrations.
No high does hook effect was observed for samples with concentrations up to 200 ng/mL.
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c. Traceability, Stability, Expected values (controls, calibrators, or methods):
## Calibrator
The instrument calculates the CRP concentration of patient specimen by use of a lot specific calibration curve that is stored in an RFID card provided with each hsCRP POC kit. The RFID card is inserted in the SMART analyzer and is needed for every single run.
The hsCRP POC assay calibration is traceable to Diazyme CRP calibrators (k103557) which are in turn traceable to IFCC International Reference Preparation for C Reactive Protein in the human serum reference material ERM®-DA472/IFCC.
## Control material
Control material target values are assigned based on the mean of replicate values on the SMART analyzer. The range is assigned as the mean +/- 15%. Stability protocols and criteria were included within the 510(k).
Stability testing was provided to support the claim of 1 month at 2-8 degrees C for opened vials, and 12 month shelf life. Real-time stability studies are ongoing.
## d. Detection limit:
LOB and LOD were calculated based on CLSI EP17-A: Protocols for Determination of Limits of Detection and Limits of Quantitation using whole blood samples (except for true blanks which were phosphate buffered saline. Based on this analysis:
LoB was estimated as 0.055 mg/L. LoD was estimated as 0.15 mg/L.
To calculate the LoQ of the Diazyme hsCRP POC Test, five patient whole blood samples were diluted to concentrations of 0.1, 0.2, 0.3, 0.5, and 1.0 mg/L. The diluted samples were tested with the Diazyme hsCRP POC Test on SMART analyzers for 20 replicates over 5 days. At the claimed LoQ of 0.47 (CV observed in this evaluation was 17% and observed bias was 8.4%.
The sponsor’s claimed measuring range is 0.47 – 23 mg/L.
## e. Analytical specificity:
### Common endogenous substance interference
Potential interferents were evaluated using whole blood samples containing
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"low" (near 1 mg/dL CRP) and "high" (4-5 mg/dL CRP) C Reactive Protein spiked with various concentrations of substances according to Clinical and Laboratory Standards Institute EP7-A "Interference Testing in Clinical Chemistry": dose-response guidelines. Each sample spiked with interference substances was tested in triplicates and compared to control samples without potential interferents.
The interference substances examined and their concentrations tested are listed in the following table:
| Compound tested | Maximum interferent concentration tested | Maximum interferent concentration tested/ or at which no significant* interference was observed |
| --- | --- | --- |
| Ascorbic acid | 176 mg/dL | 176 mg/dL |
| Bilirubin | 40 mg/dL | 40mg/dL |
| Conjugated Bilirubin | 40 mg/dL | 30mg/dL. |
| Triglycerides | 1000 mg/dL | 1000 mg/dL |
| Hemoglobin | 20 g/dL | 20 g/dL |
| Rheumatoid Factor | 375 IU/mL | 250 IU/mL. |
Additional potential interferents were evaluated using whole blood samples containing concentrations of CRP below 1 mg/dL. Each sample spiked with interference substances was tested in triplicates and compared to control samples without potential interferents. Results are tabulated below:
| Compound tested | Maximum interferent concentration tested | Maximum interferent concentration tested/ or at which no significant* interference was observed |
| --- | --- | --- |
| Oxaloacetate | 300 uM | 200 uM |
| Glutathione | 300 uM | 200 uM |
| Isoniazid | 300 uM | 200 uM. |
| L-Dopa | 300 uM | 200 uM |
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* The Sponsors defines significant interference as > 10% change in recovery..
f. Assay cut-off:
Not applicable – this is a quantitative assay.
2. Comparison studies:
a. Method comparison with predicate device:
Internal testing:
A total of forty (after excluding one sample that was out of the assay detection range) EDTA whole blood specimens were tested with Diazyme hsCRP POC Test on SMART analyzer. The correspondent plasma samples were tested with Diazyme hsCRP Assay on Hitachi 917 analyzer (predicate k103557). The regression results are summarized in the following table:
| | Whole blood application |
| --- | --- |
| n | 40 |
| Slope
(w/ 95% Confidence Interval) | 0.9871
(0.8122-1.0325) |
| Intercept
(w/ 95% Confidence Interval) | -0.4004
(-0.2810 to 0.0540) |
| Correlation coefficient | 0.9511 |
| Range of values | 0.47-22.50 |
POL site testing:
One hundred and twenty (120) paired human whole blood-serum samples (a tube of venous whole blood and a tube of serum from the same individual) were tested for comparison. At each site of the three sites, 40 whole blood samples were tested using SMART analyzers. The corresponding one hundred and twenty (120) plasma specimens were tested on Hitachi 917 with predicate device (K103557) at Diazyme Laboratories. One hundred and sixteen were used after excluding four samples that were out of the assay detection range. The regression results are summarized in the following table:
| | Site 1 | Site 2 | Site 3 | 3POL Site Combined |
| --- | --- | --- | --- | --- |
| n | 38 | 39 | 39 | 116 |
| Slope
(w/ 95% Confidence | 0.9195
(0.8996 - 0.9927) | 1.0125
(0.9508 - 1.0484) | 1.0073
(0.9017 - 1.0369) | 0.9712
(0.9420 - 1.0056) |
| Intercept
(w/ 95% Confidence Interval) | -0.3556
(-0.3064 to 0.0001) | | | |
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| Interval) | | | | |
| --- | --- | --- | --- | --- |
| Intercept (w/ 95% Confidence Interval) | 0.0531 (-0.0395 - 0.1689) | -0.0839 (-0.1744 - 0.1349) | -0.2795 (-0.3237 - 0.0040) | -0.0870 (-0.0463 - 0.0686) |
| Correlation coefficient | 0.9889 | 0.9811 | 0.9858 | 0.9836 |
| Range of values | 0.60-19.55 | 0.47-14.00 | 0.51-22.79 | 0.47-22.79 |
b Matrix comparison:
Not applicable – the assay is for use in whole blood EDTA samples.
3. Clinical studies:
a. Clinical Sensitivity: Not applicable; Clinical sensitivity and specificity is not typically provided in 510(k)s for this type of assay.
b. Clinical specificity: See a, above.
c. Other clinical supportive data (when a. and b. are not applicable):
4. Clinical cut-off:
See "Expected values" Section, below.
5. Expected values/Reference range:
To verify the transferability of the reference interval from the predicate device, whole blood samples from 150 apparently healthy individuals were tested using the Diazyme hsCRP POC Test according to CLSI C28-A3 guideline.
The expected normal range is $< 5.0 \, \mathrm{mg/L}$ in $95\%$ of the population tested.
N. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.
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O. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
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