SYNCHRON SYSTEMS ENZYMATIC CO2 (CO2E) REAGENT, MODEL A60291

K091153 · Beckman Coulter, Inc. · KHS · Jul 13, 2009 · Clinical Chemistry

Device Facts

• Record ID: K091153
• Device Name: SYNCHRON SYSTEMS ENZYMATIC CO2 (CO2E) REAGENT, MODEL A60291
• Applicant: Beckman Coulter, Inc.
• Product Code: KHS · Clinical Chemistry
• Decision Date: Jul 13, 2009
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1160
• Device Class: Class 2

Indications for Use

CO2E reagent, when used in conjunction with UniCel® DxC 800 System and SYNCHRON® Systems AQUA CAL 1 and 3, is intended for the quantitative determination of Carbon Dioxide in human serum or plasma. Carbon dioxide measurements are used in the diagnosis and treatment of numerous potentially serious disorders associated with changes in body acid-base balance.

Device Story

SYNCHRON Systems Enzymatic CO2 (CO2E) Reagent is an in vitro diagnostic assay for quantitative CO2 measurement in human serum or plasma. Used on UniCel DxC 800 System; operated by laboratory personnel. Reagent contains phosphoenolpyruvate (PEP), phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase, and NADH analog. Principle: PEPC catalyzes reaction between PEP and bicarbonate to yield oxaloacetate; oxaloacetate reduced by NADH analog to malate via malate dehydrogenase. Decrease in absorbance at 410nm measured spectrophotometrically; proportional to CO2 concentration. Results assist clinicians in diagnosing/treating acid-base balance disorders. Reagent packaged in 300-test cartridges; requires AQUA CAL 1 and 3 calibrators.

Clinical Evidence

Bench testing only. Precision evaluated per CLSI EP5-A2 (N=80 per sample). Linearity (5-45 mmol/L) per CLSI EP6-A (R²=0.9967). Limit of Detection (5.0 mmol/L) per CLSI EP17-A. Interference testing per CLSI EP7-A2 showed no significant interference from bilirubin, hemoglobin, acetoacetic acid, or lipemia. Method comparison (N=99) against predicate yielded y = 0.978x + 0.35; r = 0.996. Matrix comparison confirmed suitability of lithium heparin, sodium heparin, and potassium oxalate/sodium fluoride anticoagulants.

Technological Characteristics

Quantitative enzymatic assay. Reagents: Tris-buffer (pH 7.6), PEP, PEPC, malate dehydrogenase, NADH analog, stabilizers, surfactant, preservative. Sensing principle: Spectrophotometric measurement of absorbance decrease at 410nm. Analytical range: 5.0-45.0 mmol/L. Traceable to NIST SRM 351. Instrument: UniCel DxC 800. Calibration: Every 72 hours. Storage: 2-8°C.

Indications for Use

Indicated for quantitative determination of Carbon Dioxide in human serum or plasma to assist in diagnosis and treatment of disorders associated with acid-base balance changes. No specific age or gender restrictions provided.

Regulatory Classification

Identification

A bicarbonate/carbon dioxide test system is a device intended to measure bicarbonate/carbon dioxide in plasma, serum, and whole blood. Bicarbonate/carbon dioxide measurements are used in the diagnosis and treatment of numerous potentially serious disorders associated with changes in body acid-base balance.

Predicate Devices

• UniCel DxC 600/800 SYNCHRON Clinical Systems CO2 rate pH (k042291)

Submission Summary (Full Text)

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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
ASSAY ONLY TEMPLATE

A. 510(k) Number:
k091153

B. Purpose for Submission:
New device

C. Measurand:
Carbon Dioxide (CO₂)

D. Type of Test:
Quantitative enzymatic assay

E. Applicant:
Beckman Coulter, Inc.

F. Proprietary and Established Names:
SYNCHRON Systems Enzymatic CO2 (CO2E) Reagent

G. Regulatory Information:
1. Regulation section:
21 CFR 862.1160, Bicarbonate/Carbon Dioxide Test System
2. Classification:
Class II
3. Product code:
KHS - Enzymatic, Carbon-Dioxide
4. Panel:
Clinical Chemistry (75)

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H. Intended Use:

1. Intended use(s):

See indications for use below

2. Indication(s) for use:

CO2E reagent, when used in conjunction with UniCel® DxC 800 System and SYNCHRON® Systems AQUA CAL 1 and 3, is intended for the quantitative determination of Carbon Dioxide in human serum or plasma. Carbon dioxide measurements are used in the diagnosis and treatment of numerous potentially serious disorders associated with changes in body acid-base balance.

3. Special conditions for use statement(s):

For prescription use only

4. Special instrument requirements:

UniCel® DxC 800 System

I. Device Description:

The SYNCHRON Enzymatic CO2 (CO2E) Reagent contains two 300-test cartridges that are packaged separately from the associated calibrator. The reagent cartridge contains the following ingredients: Tris-buffer (pH 7.6), phosphoenolpyruvate (PEP), phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase, NADH analog, activators, stabilizers, a surfactant and a preservative.

The SYNCHRON® Systems AQUA CAL 1 and 3 are aqueous solutions which were cleared in k965240. AQUA CAL 3 is spiked with bicarbonate to achieve a CO2 concentration of 30.0 mmol/L, while AQUA CAL 1 contains 0.0 mmol/L of CO2.

J. Substantial Equivalence Information:

1. Predicate device name(s):

UniCel DxC 600/800 SYNCHRON Clinical Systems CO2 rate pH

2. Predicate 510(k) number(s):

k042291

3. Comparison with predicate:

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| Similarities and Differences | | |
| --- | --- | --- |
| Item | Candidate device | Predicate device (k042291) |
| Intended Use | CO2E reagent, when used in conjunction with UniCel® DxC 800 System and SYNCHRON® Systems AQUA CAL 1 and 3, is intended for the quantitative determination of Carbon Dioxide in human serum or plasma. | ISE Electrolyte Buffer reagent, ISE Electrolyte Reference reagent, CO2 Alkaline Buffer and CO2 Acid reagent, when used in conjunction with SYNCHRON LX® Systems, UniCel® DxC 600/800 Systems and SYNCHRON® Systems AQUA CAL 1 and 3, are intended for quantitative determination of Carbon Dioxide concentration in human serum or plasma |
| Sample Types | Serum or Plasma | Same |
| Limit of Detection | 5.0 mmol/L | Same |
| Analytical Range | 5.0 - 45.0 mmol/L | 5.0 - 50.0 mmol/L |
| Sample Volume | 6 μl | 40 μl |
| Methodology | Enzymatic method | pH rate change method |
| Instrument Platforms | UniCel DxC 800 System | SYNCHRON LX and UniCel DxC 600/800 Systems |
| Calibration Frequency | Every 72 hours | Every 24 hours |

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

Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline – Second Edition (CLSI EP5-A2)

Evaluation of the Linearity of Quantitative Measuring Procedures: A Statistical Approach; Approved Guideline (CLSI EP6-A)

Interference Testing in Clinical Chemistry; Approved Guideline – Second Edition (CLSI E7-A2)

Protocols for Determination of Limits of Detection and Limits of Quantitation; Approved Guideline (CLSI EP17-A)

Method Comparison and Bias Estimation Using Patient Samples; Approved Guideline – Second Edition (CLSI EP9-A2)

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How to Define and Determine Reference Intervals in the Clinical Laboratory; Approved Guideline – Second Edition (CLSI C28-A2)

## L. Test Principle:

The SYNCHRON Systems CO2E assay is an enzymatic method utilizing phosphoenolpyruvate carboxylase (PEPC) and a stabilized NADH analog in two coupled enzymatic reactions. In the first reaction, PEPC catalyzes the reaction between the phosphoenolpyruvate (PEP) and $\mathrm{HCO}_3^-$ to yield oxaloacetate and inorganic phosphate. In the second step, oxaloacetate is reduced by a stable NADH analog to malate in the presence of malate dehydrogenase (MDH). The resulting decrease in absorbance at $410\mathrm{nm}$ is spectrophotometrically measured and is directly proportional to the CO2 concentration in the test sample via measurement of bicarbonate ions $(\mathrm{HCO}_3^-)$.

The chemical reaction scheme follows:


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

### 1. Analytical performance:

#### a. Precision/Reproducibility:

The sponsor performed precision studies in accordance with the CLSI EP5-A2 guideline. One serum pool and three serum controls were used to evaluate the within-run and total imprecision. Samples were analyzed in duplicate, twice a day, for 20 days. Results are summarized below:

UniCel DxC 800 SYNCHRON Clinical System

| Sample | Mean (mmol/L) | S.D. (mmol/L) | %C.V. | N |
| --- | --- | --- | --- | --- |
| Within-Run Imprecision | | | | |
| SYNCHRON Control Level 1 | 11.50 | 0.39 | 3.4 | 80 |
| SYNCHRON Control Level 2 | 19.55 | 0.45 | 2.3 | 80 |
| SYNCHRON Control Level 3 | 27.50 | 0.52 | 1.9 | 80 |
| Serum Pool | 21.60 | 0.61 | 2.8 | 80 |
| Total Imprecision | | | | |
| SYNCHRON Control Level 1 | 11.50 | 0.53 | 4.6 | 80 |
| SYNCHRON Control Level 2 | 19.55 | 0.55 | 2.8 | 80 |
| SYNCHRON Control Level 3 | 27.50 | 0.68 | 2.5 | 80 |
| Serum Pool | 21.60 | 0.74 | 3.4 | 80 |

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b. Linearity/assay reportable range:

The sponsor performed linearity studies in accordance with the CLSI EP6-A guideline. The study protocol utilized inter-dilutions of a patient serum specimen with a zero-level (saline) sample. A high CO2 level was prepared by spiking with bicarbonate solution. Seven different levels of CO2 concentrations (ranging 5 to 47 mmol/L) were tested in triplicate on the DxC 800 analyzer. The recovered CO2 values were plotted against the expected values and an appropriate line fitted by standard linear regression resulting in: $y = 0.9979x + 1.121$; $R^2 = 0.9967$.

The claimed measuring range of this device is 5.0 to $45.0\mathrm{mmol / L}$.

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

The enzymatic CO2 assay is traceable to NIST SRM 351.

AQUA CAL 1 and 3 calibrators were previously cleared under k965240.

The sponsor states that the unopened CO2E reagent is stable until the expiration date when stored at 2 to $8^{\circ}\mathrm{C}$, and for 14 days at 2 to $8^{\circ}\mathrm{C}$ once opened. The calibrators are stable unopened until the expiration date when stored at 2 to $8^{\circ}\mathrm{C}$, and for 30 days at room temperature after opening unless the expiration date is exceeded.

d. Detection limit:

The sponsor determined the limit of detection (LoD) according to the CLSI EP-17-A guideline. LoD is defined as the actual concentration at which an observed test result is very likely to exceed the limit of blank (LoB) and may therefore be declared as "detected".

The limit of the blank (LoB) was determined by analyzing a blank sample (deionized water) 20 times on a DxC 800 analyzer. To determine the LoD an aqueous CO2 standard at $5\mathrm{mmol / L}$ was used as the $100\%$ sample, while $80\%$ and $60\%$ samples were prepared by diluting the standard with deionized water. These 3 low concentration standards were analyzed 20 times each. The results demonstrated that the LoD is $5.0\mathrm{mmol / L}$.

The claimed measuring range of this assay is 5.0 to $45.0\mathrm{mmol / L}$.

e. Analytical specificity:

The sponsor performed interference studies according to the EP7-A2 guideline. Patient sample pools representing low ($\sim 20$ mmol/L), mid (22 to 28 mmol/L) and high (35 mmol/L) analytes levels were used. Five levels of each interferent were

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tested in replicates of four on a DxC 800 analyzer. The level of interference was considered not significant if there was no more than 2 mmol/L or 6% difference between the interferent result and the reference result.

No significant interferences were found for bilirubin (unconjugated) up to 40 mg/dL, hemoglobin up to 500 mg/dL, acetoacetic acid up to 250 mg/dL, lipemia up to 500 mg/dL of Intralipid or up to a serum index of 6.

f. Assay cut-off:

Not Applicable

2. Comparison studies:

a. Method comparison with predicate device:

Method comparisons to the predicate device were performed in accordance with the CLSI EP9-A2 guideline using the DxC 800 analyzer. A total of 99 serum samples were used, some samples were spiked and diluted to fully span the claimed measuring range. The range of the samples tested was 5 to 44 mmol/L. The CO2E recovery results (Y) were compared to the corresponding CO2 ISE recovery results (X) and Deming regression analysis was performed resulting in: y = 0.978x + 0.35; r = 0.996.

b. Matrix comparison:

The sponsor performed matrix comparisons using 59 apparently health subjects. Serum samples and plasma samples (lithium heparin, sodium heparin, and potassium oxalate/sodium fluoride) were drawn from the same donor. CO2 samples ranging from 25 to 32 mmol/L were analyzed on the DxC 800. The plasma results (Y) were compared to the corresponding serum results (X) for the same donor and Deming regression analysis was performed. The sponsor claimed that lithium heparin, sodium heparin, and potassium oxalate/sodium fluoride are acceptable anticoagulants to be used. Results are summarized below.

Anticoagulant Study Summary

| Anticoagulant | Level Tested for In Vitro Interference | Deming Regression Analysis |
| --- | --- | --- |
| Lithium Heparin | 14 units/mL | Y = 1.052X – 1.129; r = 0.826 |
| Sodium Heparin | 14 units/mL | Y = 1.000X – 0.221; r = 0.910 |
| Potassium Oxalate / Sodium Fluoride | 2.0 / 2.5 mg/dL | Y = 1.014X – 0.553; r = 0.922 |

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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

5. Expected values/Reference range:
The reference range is 23-29 mmol/L based on the following literature:
Wu, A., ed., Tietz Clinical guide to Laboratory Tests 4th Edition, Saunders Elsevier, St. Louis, MO (2006).
The sponsor recommends that each laboratory establish its own reference intervals based on upon its patient population.

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.