Randox Calcium (Ca)

K182042 · Randox Laboratories, Ltd. · CJY · Oct 23, 2018 · Clinical Chemistry

Device Facts

• Record ID: K182042
• Device Name: Randox Calcium (Ca)
• Applicant: Randox Laboratories, Ltd.
• Product Code: CJY · Clinical Chemistry
• Decision Date: Oct 23, 2018
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1145
• Device Class: Class 2

Indications for Use

The Randox Calcium (Ca) device is intended for the quantitative in vitro determination of calcium concentration in serum, plasma and urine. This product is suitable for use on the RX series analyzer, RX daytona plus. Such measurements are used in the diagnosis and treatment of parathyroid disease, a variety of bone diseases and chronic renal failure.

Device Story

Randox Calcium (Ca) is a quantitative, colorimetric in vitro diagnostic assay; utilizes Arsenazo III reagent to bind calcium ions in serum, plasma, or urine samples; forms colored complex measured at 660 nm; intensity of color directly proportional to calcium concentration. Used on RX daytona plus analyzer; operated by laboratory personnel. Output provides calcium concentration values (mg/dL) to clinicians for diagnosis/treatment of parathyroid, bone, and renal diseases. Includes auto-dilution feature for samples exceeding reportable range.

Clinical Evidence

Bench testing only. Precision evaluated per CLSI EP05-A3; linearity per CLSI EP6-A; method comparison per CLSI EP09-A2. Serum precision (CV 2.1-4.2%); urine precision (CV 2.0-4.6%). Linearity confirmed 1.0-16 mg/dL (serum) and 1.0-32 mg/dL (urine). Method comparison against predicate (n=111 serum, n=100 urine) showed high correlation (r=0.99). Matrix comparison (serum vs. lithium heparin plasma) showed r=0.99. Interference testing confirmed no significant impact from common endogenous/exogenous substances.

Technological Characteristics

Colorimetric assay; Arsenazo III reagent (230 μmol/L) with sodium acetate buffer (54.4 mmol/L). Liquid, ready-to-use reagent. Measuring range: 1.0–16.0 mg/dL (serum/plasma), 1.0–32.0 mg/dL (urine). Analyzed on RX daytona plus system. Traceable to NIST 909b and SRM956b reference materials.

Indications for Use

Indicated for the quantitative in vitro determination of calcium concentration in serum, plasma, and urine to aid in the diagnosis and treatment of parathyroid disease, bone diseases, and chronic renal failure.

Regulatory Classification

Identification

A calcium test system is a device intended to measure the total calcium level in serum. Calcium measurements are used in the diagnosis and treatment of parathyroid disease, a variety of bone diseases, chronic renal disease and tetany (intermittent muscular contractions or spasms).

Predicate Devices

• Siemens Healthcare Diagnostics ADVIA Chemistry Calcium_2 Method (k083386)

Submission Summary (Full Text)

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

A. 510(k) Number:
k182042

B. Purpose for Submission:
New device

C. Measurand:
Calcium

D. Type of Test:
Quantitative, colorimetric

E. Applicant:
Randox Laboratories Ltd.

F. Proprietary and Established Names:
Randox Calcium (Ca)

G. Regulatory Information:
1. Regulation section:
21 CFR 862.1145 – Calcium test system
2. Classification:
Class II
3. Product code:
CJY

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4. Panel:
Chemistry (75)

H. Intended Use:

1. Intended use(s):
Refer to Indications for use

2. Indication(s) for use:
The Randox Calcium (Ca) device is intended for the quantitative in vitro determination of calcium concentration in serum, plasma and urine. This product is suitable for use on the RX series analyzer, RX daytona plus. Such measurements are used in the diagnosis and treatment of parathyroid disease, a variety of bone diseases and chronic renal failure.

3. Special conditions for use statement(s):
For prescription use only.

4. Special instrument requirements:
RX daytona plus

I. Device Description:
The Randox Calcium (Ca) assay kit consists of a ready to use reagent solution that contains sodium acetate (54.2 mmol/L, pH 5.9), arsenazo (approximately 230 μmol/L) and non-reactive stabilizers.

J. Substantial Equivalence Information:

1. Predicate device name(s):
Siemens Healthcare Diagnostics ADVIA Chemistry Calcium_2 Method

2. Predicate 510(k) number(s):
k083386

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3. Comparison with predicate:

| Similarities | | |
| --- | --- | --- |
| Item | Candidate Device – Randox Calcium (Ca) k182042 | Predicate Device - ADVIA Chemistry Calcium_2 k083386 |
| Intended Use | Quantitative in vitro determination of calcium concentration in serum, plasma and urine | Same |
| Methodology | Arsenazo III | Same |
| Reagent Composition | Liquid ready to use | Same |
| Reagent Stability | To expiration date when stored at 15 – 25°C | Same |
| Acceptable Matrices | Serum, plasma, and urine | Same |
| Measuring Range | Serum/Plasma 1.0 – 16.0 mg/dL Urine 1.0 – 32.0 mg/dL | Same |
| Differences | | |
| --- | --- | --- |
| Item | Candidate Device – Randox Calcium (Ca) k182042 | Predicate Device - ADVIA Chemistry Calcium_2 k083386 |
| Reagent Components and Concentrations | Sodium acetate (pH 5.9) 54.4 mmol/L | Sodium acetate (pH 5.9) 54.4 mmol/L |
| | Arsenazo III 230 μmol/L | Arsenazo III 188 μmol/L |

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

1. CLSI. Interference Testing in Clinical Chemistry; Approved Guideline - Second Edition (EP07-A2)
2. CLSI. Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach; Approved Guideline (EP06-A)
3. CLSI. Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline - Third Edition (EP28-A3c)
4. CLSI. Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures; Approved Guideline - Second Edition (EP17-A2)
5. CLSI. Evaluation of Precision of Quantitative Measurement Procedures; Approved Guideline - Third Edition (EP05-A3)

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L. Test Principle:

The Randox Calcium (Ca) reagent uses the Arsenazo III assay protocol. Arsenazo III specifically binds to calcium forming a colored complex at 660 nm.

$$
\mathrm{Ca}^{++} + \text{Arsenazo} \rightarrow \text{III Colored complex}
$$

The amount of calcium present in the sample is directly proportional to the intensity of the colored complex formed.

M. Performance Characteristics (if/when applicable):

1. Analytical performance:

a. Precision/Reproducibility:

Precision was evaluated consistent with the CLSI EP05-A3 guideline. Separate precision studies were conducted for serum and urine matrices and were performed using one operator on one RX daytona plus system.

The serum precision study analyzed human serum samples spiked with calcium chloride (CaCl₂) to the concentrations listed in the table below. Testing was conducted twice per day for 20 non consecutive days. Two replicates per run was performed for each sample. Two reagent lots were evaluated and the results were comparable between the lots. Representative performance from one lot is presented below:

Serum Within-Run Precision

| | Level 1 | Level 2 | Level 3 | Level 4 |
| --- | --- | --- | --- | --- |
| Mean (mg/dL) | 3.89 | 6.61 | 10.78 | 13.95 |
| SD (mg/dL) | 0.12 | 0.16 | 0.28 | 0.32 |
| CV (%) | 3.1 | 2.4 | 2.6 | 2.3 |
| n | 80 | 80 | 80 | 80 |

Serum Total Imprecision

| | Level 1 | Level 2 | Level 3 | Level 4 |
| --- | --- | --- | --- | --- |
| Mean (mg/dL) | 3.85 | 6.65 | 10.7 | 13.83 |
| SD (mg/dL) | 0.16 | 0.28 | 0.44 | 0.56 |
| CV (%) | 4.2 | 4.2 | 4.1 | 4.0 |
| n | 80 | 80 | 80 | 80 |

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Urine precision studies were performed for calcium using two levels of urine controls, calibration material and human urine samples. Testing was conducted twice per day for 20 non consecutive days. Two replicates per run was performed for each sample. Two reagent lots were evaluated and the results were comparable between the lots. Representative performance from one lot is presented below:

Urine Within-Run Precision

| | Level 1 | Level 2 | Level 3 | Level 4 |
| --- | --- | --- | --- | --- |
| Mean (mg/dL) | 6.05 | 7.94 | 15.07 | 25.97 |
| SD (mg/dL) | 0.16 | 0.16 | 0.40 | 0.56 |
| CV (%) | 2.6 | 2.0 | 2.7 | 2.2 |
| n | 80 | 80 | 80 | 80 |

Urine Total Imprecision

| | Level 1 | Level 2 | Level 3 | Level 4 |
| --- | --- | --- | --- | --- |
| Mean (mg/dL) | 6.05 | 7.94 | 15.07 | 25.97 |
| SD (mg/dL) | 0.28 | 0.32 | 0.60 | 1.00 |
| CV (%) | 4.6 | 4.0 | 4.0 | 3.9 |
| n | 80 | 80 | 80 | 80 |

## b. Linearity/assay reportable range:

The sponsor performed linearity studies referencing the CLSI EP6-A guideline. Serum and urine linearity samples were prepared at eleven levels, including concentrations above and below the claimed measuring range of the assay. Each level was run in replicates of five on two lots of Calcium reagent on a single day. Recoveries for serum samples ranged from 95.1 – 106.0% and linear regression analysis of a representative lot produced the following results:

Serum: $y = 1.02x + 0.04, r = 1.00$

Recoveries for urine samples ranged from 90.7 – 104.2% and linear regression analysis of a representative lot produced the following:

Urine: $y = 0.98x + 0.28, r = 1.00$

The results of the linearity study support the sponsor's claimed measuring range of 1.0 to 16.0 mg/dL for serum and plasma and 1.0 to 32.0 mg/dL for urine.

Automatic Dilution:

The Rx Daytona plus analyzer has an auto-dilution feature. When a calcium concentration exceeds the upper end of the reportable range (16 mg/dL for serum and 32 mg/dL for urine), the result is flagged, and the sample is diluted with saline and re-run automatically by the instrument.

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The sponsor performed a study to evaluate the auto-dilution feature and the results supported the sponsor's claim that the instrument could automatically and accurately dilute the out of range high concentration samples.

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

Traceability for the Randox Calcium (Ca) reagent is standardized against primary calibrators traceable to Calcium reference materials NIST 909b and SRM956b.

d. Detection limit:

A limit of blank (LoB), a limit of detection (LoD) and a limit of quantitation (LoQ) studies were performed for both serum and urine using two lots of Randox Calcium (Ca) reagent tested by one operator on one RX daytona plus system.

## Serum

The limit of blank (LoB) was evaluated using four blank samples which were run in replicates of five over three days for a total of 15 replicates per sample. The LoB was calculated to be 0.02 mg/dL as the 95th percentile of the 60 results sorted from low to high.

The limit of detection (LoD) was calculated to be 0.18 mg/dL based on 240 determinations using 4 samples with low calcium concentrations. The formula used was LoB value + CpSDL where Cp is derived from the 95th percentile of the standard Gaussian distribution, and SDL is the estimated standard deviation of the 4 low level samples tested.

The limit of quantitation (LoQ) was determined as the lowest concentration at which precision and accuracy are still met, with acceptable criteria ≤20% accuracy and ≤20% imprecision. The data was collected over five days.

The two lots evaluated produced LoQ's of 0.41 mg/dL and 0.53 mg/dL. The sponsor claims 0.53 mg/dL as LoQ for the candidate device.

## Urine

The LoB was evaluated using four blank samples which were run in replicates of five over three days for a total of 15 replicates per sample. The LoB was calculated to be 0.08 mg/dL as the 95th percentile of the 60 results sorted from low to high.

The LoD was calculated to be 0.15 mg/dL based on 240 determinations using 4 samples with low calcium concentrations. The formula used was LoB value + CpSDL where Cp is derived from the 95th percentile of the standard Gaussian distribution, and SDL is the estimated standard deviation of the 4 low level samples tested.

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The LoQ was determined as the lowest concentration at which precision and accuracy are still met, with acceptable criteria $\leq 20\%$ accuracy and $\leq 20\%$ imprecision.

Two lots achieved LoQ's of $0.60\mathrm{mg / dL}$ and $0.55\mathrm{mg / dL}$ . The sponsor claims an LoQ of $0.60\mathrm{mg / dL}$ for the candidate device.

The sponsor claims a measuring range of 1.0 to $16.0\mathrm{mg / dL}$ for serum and plasma and 1.0 to $32.0\mathrm{mg / dL}$ for urine.

# e. Analytical specificity:

The effects of potential interferents were determined separately for the serum and urine matrices. The sponsor defined interference as $\geq 10\%$ with the potential interferent as compared to the control sample.

For serum the following analytes were tested and shown not to interfere up to the levels indicated at calcium concentrations of $8\mathrm{mg / dL}$ and $12\mathrm{mg / dL}$ . The highest concentration tested that did not cause interference is listed in the table below:

| Substance | Highest level tested that showed no interference |
| --- | --- |
| Hemoglobin | 1000 mg/dL |
| Total Bilirubin | 60 mg/dL |
| Conjugated Bilirubin | 60 mg/dL |
| Triglycerides | 2000 mg/dL |
| Intralipid | 1315 mg/dL |
| Ascorbic Acid | 6 mg/dL |

For urine the following analytes were tested and shown not to interfere up to the levels indicated at calcium concentrations of $9.0\mathrm{mg / dL}$ and $22.8\mathrm{mg / dL}$ . The highest concentration tested that did not cause interference is listed in the table below:

| Substance | Highest level tested that showed no interference |
| --- | --- |
| Hemoglobin | 250 mg/dL |
| Total Bilirubin | 60 mg/dL |
| Conjugate Bilirubin | 60 mg/dL |
| Ascorbic Acid | 200 mg/dL |
| Ethanol | 1000 mg/dL |
| Boric Acid | 1000 mg/dL |
| Gamma Globulin | 500 mg/dL |
| Glucose | 2000 mg/dL |
| Human Serum Albumin | 500 mg/dL |
| Sodium Oxalate | 100 mg/dL |
| Sodium Fluoride | 1000 mg/dL |
| Sodium Chloride | 4000 mg/dL |

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f. Assay cut-off:

Not applicable.

2. Comparison studies:

a. Method comparison with predicate device:

The sponsor performed a method comparison on de-identified serum and urine samples between the candidate device and the predicate (ADVIA Chemistry Calcium_2 (CA_2) method cleared under k083386. Two lots of the candidate device were evaluated with similar performance. Representative data from one lot is presented below:

Serum Method Comparison

One hundred and eleven (111) serum patient samples ranging from 1.00 to 15.87 mg/dL were tested on the RX daytona plus analyzer and the predicate in singlicate. Three diluted and eight spiked samples were included in the analysis. Linear regression analysis produced the following equation:

$$
y = 0.99x - 0.10, r = 0.99
$$

Urine Method Comparison

One hundred (100) urine patient samples ranging from 1.20 to 31.78 mg/dL were tested on the RX daytona plus analyzer and the predicate in singlicate. Four diluted and three spiked samples were included in the analysis. Linear regression analysis produced the following equation:

$$
y = 0.98x - 0.24, r = 0.99
$$

b. Matrix comparison:

A matrix comparison study was performed to evaluate the use of plasma samples on one RX daytona plus system using two lots of Calcium reagents. Patient samples were drawn in matched pairs – one sample serum (x) and the second sample lithium heparin plasma (y). Forty-seven (47) matched patient sample pairs were analyzed in singlicate spanning the range 1.00 to 14.11 mg/dL. The performance between the two reagent lots tested was similar and the following linear regression equation is representative:

$$
y = 0.97x + 0.22, r = 0.99
$$

The results of the matrix comparison study support the claim that serum and lithium heparin plasma samples can be used with the Randox Calcium (Ca) assay.

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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:

Reference ranges for adults are cited from the literature:
Serum: 9.02 – 11.6 mg/dL
Urine: 100 – 249 mg/24 hours

The sponsor includes the following statement in the labeling:

It is recommended that each laboratory establish its own reference range to reflect the age, sex, diet and geographical location of the population.

References cited:
Barnett, R.N., et al. (1973) Amer. J. Clin. Path. 59:836.
Mosby's Manual of Diagnostic and Laboratory Tests (2006) p153.

N. Proposed Labeling:

The labeling is sufficient and it satisfies the requirements of 21 CFR Parts 801 and 809, as applicable.

O. Conclusion:

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