IDS-ISYS 25-HYDROXY VITAMIN D ASSAY, IDS-ISYS 25-HYDROXY VITAMIN D CONTROL SET

K091849 · Immunodiagnostic Systems, Inc. · MRG · Jun 25, 2010 · Clinical Chemistry

Device Facts

• Record ID: K091849
• Device Name: IDS-ISYS 25-HYDROXY VITAMIN D ASSAY, IDS-ISYS 25-HYDROXY VITAMIN D CONTROL SET
• Applicant: Immunodiagnostic Systems, Inc.
• Product Code: MRG · Clinical Chemistry
• Decision Date: Jun 25, 2010
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1825
• Device Class: Class 2

Indications for Use

The IDS-iSYS Multi-Discipline Automated Analyzer is a discrete continuous loading chemiluminescent immunoassay analyzer for in vitro diagnostic use. The IDS-iSYS 25-Hydroxy Vitamin D Assay is intended for the quantitative determination of 25-hydroxyvitamin D (25-OH D) and other hydroxylated metabolites in human serum on the IDS-iSYS Multi-Discipline Automated Analyzer. Results are to be used in conjunction with other clinical and laboratory data to assist the clinician in the assessment of vitamin D sufficiency in an adult population. The kit is for in vitro diagnostic use only. The IDS-iSYS 25-Hydroxy Vitamin D Control Set is intended for use as assayed quality control samples to monitor the accuracy and precision of the IDS-iSYS 25-Hydroxy Vitamin D Assay.

Device Story

The IDS-iSYS system is a discrete, continuous-loading chemiluminescent immunoassay analyzer. It processes human serum samples to quantify 25-hydroxyvitamin D levels. The device performs automated sample pretreatment to denature Vitamin D Binding Protein, followed by neutralization and incubation with acridinium-labeled anti-25-OH D antibodies and magnetic particles. A magnet captures the particles; after washing and trigger reagent addition, the system measures emitted light, which is inversely proportional to the analyte concentration. The analyzer is intended for clinical laboratory use. Results are provided to clinicians to aid in assessing patient vitamin D status. The system includes integrated software for calibration, quality control monitoring, and data management.

Clinical Evidence

Bench testing only. Performance evaluated via precision studies (CLSI EP5-A2), linearity (CLSI EP6-A2), and method comparison (CLSI EP9-A2) against the predicate RIA. Method comparison across 348 samples showed correlation coefficients (r) of 0.94–0.96. Analytical sensitivity (LoD) is 3.6 ng/mL; functional sensitivity is 6 ng/mL. Specificity testing confirmed 100% cross-reactivity for 25-hydroxyvitamin D3, D2, and 24,25-dihydroxyvitamin D3. Interference testing identified bias with hemolysis and icterus, leading to labeling contraindications for such specimens.

Technological Characteristics

Chemiluminescent immunoassay; automated discrete continuous loading analyzer; in vitro diagnostic use; human serum sample matrix.

Indications for Use

Indicated for quantitative determination of 25-hydroxyvitamin D and other hydroxylated metabolites in human serum to assist clinicians in assessing vitamin D sufficiency in adult populations.

Regulatory Classification

Identification

A vitamin D test system is a device intended for use in clinical laboratories for the quantitative determination of 25-hydroxyvitamin D (25-OH-D) and other hydroxylated metabolites of vitamin D in serum or plasma to be used in the assessment of vitamin D sufficiency.

Special Controls

*Classification.* Class II (special controls). Vitamin D test systems must comply with the following special controls:(1) Labeling in conformance with 21 CFR 809.10 and (2) Compliance with existing standards of the National Committee on Clinical Laboratory Standards.

Submission Summary (Full Text)

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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY ASSAY AND INSTRUMENT COMBINATION TEMPLATE

A. 510(k) Number:
k091849

B. Purpose for Submission:
New device, assay and analyzer

C. Measurand:
25-hydroxyvitamin D and other hydroxylated metabolites of vitamin D

D. Type of Test:
Quantitative chemiluminescent immunoassay

E. Applicant:
Immunodiagnostic Systems Limited

F. Proprietary and Established Names:
IDS-iSYS Multi-Discipline Automated Analyzer
IDS-iSYS 25-Hydroxy Vitamin D Assay
IDS-iSYS 25-Hydroxy Vitamin D Control Set

G. Regulatory Information:
1. Regulation section:
21 CFR 862.2160 - Discrete Photometric Chemistry Analyzer for Clinical Use
21 CFR 862.1825 – Vitamin D Test System
21 CFR 862.1660 - Quality Control Material (Assayed and Unassayed)
2. Classification:
Class I, Class II, Class I reserved, respectively

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3. Product code:
JJE - Discrete Photometric Chemistry Analyzer for Clinical Use
MRG - Vitamin D Test System
JJX – Single (specified) Analyte Controls (Assayed and Unassayed)

4. Panel:
Chemistry (75)

H. Intended Use:

1. Intended use(s):
See indications for use below.

2. Indication(s) for use:
The IDS-iSYS Multi-Discipline Automated Analyzer is a discrete continuous loading chemiluminescent immunoassay analyzer for in vitro diagnostic use.

The IDS-iSYS 25-Hydroxy Vitamin D Assay is intended for the quantitative determination of 25-hydroxyvitamin D (25-OH D) and other hydroxylated metabolites in human serum on the IDS-iSYS Multi-Discipline Automated Analyzer. Results are to be used in conjunction with other clinical and laboratory data to assist the clinician in the assessment of vitamin D sufficiency in an adult population.

The kit is for in vitro diagnostic use only.

The IDS-iSYS 25-Hydroxy Vitamin D Control Set is intended for use as assayed quality control samples to monitor the accuracy and precision of the IDS-iSYS 25-Hydroxy Vitamin D Assay.

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

4. Special instrument requirements:
IDS iSYS Multi-Discipline analyzer

I. Device Description:
The IDS-iSYS 25-Hydroxy Vitamin D Assay consists of Reagent Cartridges and one

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set of calibrators (Calibrators A and B). The Reagent Cartridges contain multiple reagents: MPV1 (Magnetic particles coated with 25-OH D a phosphate buffer containing methanol with sodium azide as preservative 1 bottle), CONJ (Anti-25-OH D sheep polyclonal antibody labeled with an acridinium ester derivative, in buffer containing bovine, sheep, rabbit and mouse proteins with sodium azide as preservative), NaOH (Sodium hydroxide solution <0.5 M), and BUF (Assay buffer containing proprietary displacing compounds, methanol, and sodium azide as preservative).

Calibrators A and B contain horse serum in a buffer matrix with two defined concentrations of 25-OH D and sodium azide as a preservative.

The IDS-iSYS 25-Hydroxy Vitamin D Control Set contain horse serum in a buffer matrix with three defined concentrations of 25-OH D and sodium azide as a preservative.

## J. Substantial Equivalence Information:

1. Predicate device name(s):

IDS Gamma-B 25-Hydroxy Vitamin D RIA

2. Predicate K number(s):

k991998

3. Comparison with predicate:

| Similarities | | |
| --- | --- | --- |
| Item | Device | Predicate (k991998) |
| Intended use and indications for use | Same | Quantitative determination of 25-Hydroxyvitamin D to be used in the assessment of Vitamin D sufficiency. |
| Antibody | Same | Anti-25 OH D Sheep Polyclonal IgG |
| Calibration | Same | Traceable to U.V. quantification. |
| Differences | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Test methodology | Chemiluminescent immunoassay | Radioimmunoassay (RIA) |
| Sample pretreatment | Performed on-board the analyzer | Manual extraction |

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| Differences | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Assay procedure | Performed by the IDS-iSYS analyzer | Manual |

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

- User Evaluation of Precision Performance of Clinical Chemistry Devices: Approved Guideline (CLSI EP5-A2)
- Evaluation of the Linearity of Quantitative Measurement Procedures: a Statistical Approach: Approved Guideline (CLSI EP6-A2)
- How to Define and Determine Reference Intervals in the Clinical Laboratory; Approved Guideline (C28-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)

## L. Test Principle:

The assay is based on chemiluminescence technology. Samples are subjected to a pretreatment step to denature the Vitamin D Binding Protein (VDBP). The treated samples are then neutralized in assay buffer and a specific anti-25-OH D antibody labeled with acridinium is added. Following an incubation step, magnetic particles linked to 25-OH D are added. Following a further incubation step, the magnetic particles are "captured" using a magnet. After a washing step and addition of trigger reagents, the light emitted by the acridinium label is inversely proportional to the concentration of 25-OH D in the original sample.

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

### 1. Analytical performance:

#### a. Precision/Reproducibility:

Three serum controls (6.7, 25.8, 74.2 ng/mL) were assayed using three lots of reagents in quadruplicate (n=4) once per day for 20 days on two instruments. Each sample was individually pretreated by the IDS iSYS analyzer.

| Control | n | Mean | Within-run | | Total | |
| --- | --- | --- | --- | --- | --- | --- |
| | | (ng/mL) | SD | CV% | SD | CV% |
| 1 | 80 | 6.7 | 0.8 | 12.1% | 1.1 | 16.9% |
| 2 | 80 | 25.8 | 1.4 | 5.5% | 2.7 | 10.4% |
| 3 | 80 | 74.2 | 5.4 | 7.3% | 6.6 | 8.9% |

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A second study was performed based on CLSI EP5 A2 using a single lot of reagents. Seven (7) serum samples were assayed n=4, once per day for 20 days. Samples ranged in value from 9.7-116.9 ng/mL. Each sample was individually pretreated by the IDS iSYS analyzer.

| Sample | n | mean | Repeatability | | Within-device | |
| --- | --- | --- | --- | --- | --- | --- |
| | | (ng/mL) | SD | CV% | SD | CV% |
| 1 | 80 | 9.7 | 0.8 | 8.2% | 0.8 | 8.6% |
| 2 | 80 | 15.1 | 1.4 | 9.1% | 1.6 | 10.8% |
| 3 | 80 | 20.4 | 1.3 | 6.3% | 1.5 | 7.5% |
| 4 | 80 | 32.7 | 1.6 | 4.9% | 2.3 | 6.9% |
| 5 | 80 | 46.3 | 2.2 | 4.8% | 2.7 | 5.8% |
| 6 | 80 | 102.5 | 6.7 | 6.5% | 7.7 | 7.5% |
| 7 | 80 | 116.9 | 9.3 | 8.0% | 10.2 | 8.7% |

b. Linearity/assay reportable range:

The reportable range of the assay is 6-126 ng/mL. Linearity was evaluated based on CLSI EP-6A, "Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach". Samples were prepared by diluting a high patient sample with a low patient sample to obtain eight concentrations across the measuring range, ranging from 6 to 126 ng/mL. Each sample was assayed in duplicate. The resulting mean concentrations were compared to predicted concentrations. Regression equations for the first, second and third order polynomials were calculated. None of the nonlinear coefficients, b2 or b3, were significant (p > 0.05 for all) and therefore the dataset was considered linear.

The resulting linear regression equation was $y = 0.9965x + 0.2303$, $R^2 = 0.9965$

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

Calibrator traceability and value assignment

An internal stock solution is prepared by reconstituting a vial of 25-hydroxyvitamin D3 with ethanol and adding this to horse serum. The potency assigned to the stock solution is nominally based on the absorbance at 264nm of the ethanolic 25D solution prior to addition to the serum. A molar extinction coefficient of 18,200 is used to calculate the concentration from the absorbance value.

Kit calibrators are lot specific for each assay kit. Master calibrators and kit calibrators A and B are prepared gravimetrically from the stock solution or an

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intermediate stock solution. For value assignment, the kit calibrators are tested as unknowns in greater than 25 assay runs using one analyzer. Each run is calibrated using Master Calibrators. The mean values obtained for the kit calibrators are verified on three additional analyzers. The values must fall within specified acceptable ranges.

## Stability

The calibrator and control shelf-life and open-vial stability testing protocols and acceptance criteria were described and found to be adequate. Current shelf life studies support an eight-month shelf life, with real-time studies on-going. Once opened calibrators and controls are stable for up to 2.5 hours on board the analyzer.

## d. Detection limit:

The Limit of Blank (LoB) study was performed according to CLSI EP-17A. The zero calibrator was assayed as 10 replicates over six assays on six separate days on three separate instruments giving a total of 60 measurements. The Limit of Blank was determined by calculating the concentration corresponding to the mean zero calibrator minus two standard deviations from the 4PL calibration curve. The LoB claim is 1.8 ng/mL.

The limit of detection (LoD) study was performed by assaying ten samples with low vitamin D concentrations approximately four times the LoB, in duplicate over six assays on six days using three instruments. The LoD claim is 3.6 ng/mL.

The functional sensitivity was determined to be 6 ng/mL and is defined as the concentration of the analyte that demonstrates imprecision less than or equal to 20% CV.

## e. Analytical specificity:

The following table summarizes the specificity of the IDS-iSYS 25-Hydroxy Vitamin D Assay:

| Analyte | Cross-Reactivity |
| --- | --- |
| 25-hydroxyvitamin D_{3} | 100% |
| 25-hydroxyvitamin D_{2} | 100% |
| 24,25-dihydroxyvitamin D_{3} | 100% |
| Cholecalciferol (D_{3}) | 2.7% |
| Ergocalciferol (D_{2}) | 2.7% |

The following endogenous interferences were evaluated.

To evaluate potential lipid interference a natural specimen with lipid concentration 2083 mg/dL was obtained. A portion was delipidated and assayed

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along with the same unaltered specimen n=23 in the IDS-iSYS 25-OH assay. At vitamin D concentration 8.2 mg/dL less than 1% bias was demonstrated.

To evaluate potential biotin interference, three specimens at 13, 41, and 51 ng/mL 25-OH Vitamin D were spiked with 300 nmol/L biotin. The same specimens without added biotin (control) and the specimens with added biotin were evaluated n=23 in the IDS-iSYS 25-OH assay. Less than 10% bias was seen between the test and control samples.

To evaluate potential interference from hemolysis, three specimens at 13, 37, and 52 ng/mL 25-OH Vitamin D were spiked with hemoglobin from 25 mg/dL up to 500 mg/dL and compared to the same specimens without added hemoglobin. When evaluated using the IDS-iSYS 25-OH assay, test samples under-recovered in the range of 6-18% in the presence of 25 mg/dL hemoglobin. Specimens containing higher concentrations of hemoglobin showed more significant bias.

To evaluate potential interference from bilirubin, three specimens at 11, 42, and 66 ng/mL 25-OH Vitamin D were spiked with bilirubin from 0.3 mg/dL up to 20 mg/dL and compared to the same specimens without added bilirubin. When evaluated using the IDS-iSYS 25-OH assay, test samples over-recovered in the range of 12-14% in the presence of up to 10 mg/dL bilirubin.

The labeling states that hemolyzed or icteric specimens should not be used.

f. Assay cut-off:

Not applicable

2. Comparison studies:

a. Method comparison with predicate device:

Method comparison studies were performed following CLSI EP9-A2. Three studies were performed, one at an external site and two by the manufacturer. A total of 348 serum samples were tested in all between the three studies on the IDS-iSYS 25-Hydroxy Vitamin D Assay and the RIA the predicate. Six (6) samples were prepared by augmenting aliquots of different serum samples with endogenous high serum samples. Samples spanned the assay range with values from 6.3-113 ng/mL. Passing-Bablock regression analysis was performed.

A summary of results for each study is shown below.

Study 1-IDS

| Passing Bablock | y = 1.14x - 5.2 |
| --- | --- |
| Slope, 95% Confidence Interval | 1.06 to 1.22 |
| Intercept, 95% Confidence | -7.1 to -3.7 |

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| Interval (ng/mL) | |
| --- | --- |
| Correlation Coefficient, r | 0.94 |
| N | 127 |
| Range (ng/mL) | 7.0 to 55.9 |

# Study 2-IDS

| Passing Bablock | y = 1.02x - 3.7 |
| --- | --- |
| Slope, 95% Confidence Interval | 0.98 to 1.06 |
| Intercept, 95% Confidence Interval (ng/mL) | -5.0 to -2.3 |
| Correlation Coefficient, r | 0.96 |
| N | 127 |
| Range (ng/mL) | 6.5 to 113 |

# Study 3-External

| Passing Bablock | y = 1.05x - 0.3 |
| --- | --- |
| Slope, 95% Confidence Interval | 0.98 to 1.13 |
| Intercept, 95% Confidence Interval (ng/mL) | -1.0 to 1.6 |
| Correlation Coefficient, r | 0.95 |
| N | 94 |
| Range (ng/mL) | 6.8 to 65.3 |

b. Matrix comparison: Only serum may be used.

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:

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Not applicable

## 5. Expected values/Reference range:

An expected values study performed according to the non-parametric method in CLSI protocol C28-A2.

Samples from 150 apparently healthy male and female adults living in the south eastern United States were assayed in the IDS-iSYS 25-Hydroxy Vitamin D Assay.

The 95% reference interval was calculated by a non-parametric method following C28-A2. The following range was obtained:

Normal Adults 7.9 - 57.8 ng/mL (n=150)

The labeling states that each laboratory should determine ranges for their local population. Ranges should be based on clinical decision values that apply to both sexes of all ages rather than population based reference ranges for 25-OH D.

The sponsor cites literature in the labeling that suggests the following ranges for classification of 25-OH-Vitamin D status:

| Status | Range |
| --- | --- |
| Deficient | <10 ng/mL |
| Insufficient | 10-29 ng/mL |
| Sufficient | 30-100 ng/mL |

Heaney RP. The vitamin D requirement in health and disease. J Steroid Biochem Mol Biol 2005;97:13-9.

Hollis BW. Circulating 25-hydroxyvitamin D levels indicative of vitamin D sufficiency: implications for establishing a new effective dietary intake recommendation for vitamin D. J Nutr. 2005;135:317-322.

Holick MF. The vitamin D epidemic and its health consequences. J Nutr 2005;135:2739S-2748S.

## N. Instrument Name:

IDS iSYS Multi-Discipline analyzer

## O. System Descriptions:

1. Modes of Operation:

Continuous loading on a sample by sample basis

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2. Software:

FDA has reviewed applicant’s Hazard Analysis and software development processes for this line of product types:

Yes ☐ _x_ ☐ or No ☐

3. Specimen Identification:

Barcoding or manual entry

4. Specimen Sampling and Handling:

Samples in sample cups or tube placed into the sample tray. Specimens, calibrators and controls are pipetted by a pipetting arm into disposable cuvettes. The transfer probe is rinsed internally and externally between samples.

5. Calibration:

The results are calculated in comparison to a calibration curve. The specific reference curve (master curve) for a reagent lot is in the file containing all the data for that lot, which is provided on the CD accompanying the reagent cartridge. This information is registered in the analyzer's database when the CD is introduced on the controlling computer.

If a new reagent lot is used, this curve must be registered on the database and then adjusted by a 2 point calibration before sample results can be calculated.

6. Quality Control:

The software contains a quality control program that evaluates calibration and control results and determines if they are within specified acceptable limits.

The labeling states that controls should be tested in every run containing patient samples, during assay calibrations, or according to local regulations. Laboratories should test controls at least once per shift.

P. Other Supportive Instrument Performance Characteristics Data Not Covered In the “Performance Characteristics” Section above:

Not applicable

Q. Proposed Labeling:

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

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R. Conclusion:

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

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