INCSTAR 25-HYDROXYVITMIN D 1251 RIA

K953567 · Incstar Corp. · MRG · Sep 25, 1996 · Clinical Chemistry

Device Facts

• Record ID: K953567
• Device Name: INCSTAR 25-HYDROXYVITMIN D 1251 RIA
• Applicant: Incstar Corp.
• Product Code: MRG · Clinical Chemistry
• Decision Date: Sep 25, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1825
• Device Class: Class 2

Intended Use

The INCSTAR 25-Hydroxyvitamin D 125I RIA Kit is intended for the quantitative measurement of 25-hydroxyvitamin D and other hydroxylated vitamin D metabolites in human serum or plasma to be used in the assessment of vitamin D sufficiency.

Device Story

INCSTAR 25-Hydroxyvitamin D 125I RIA is a radioimmunoassay (RIA) kit for quantitative measurement of 25-hydroxyvitamin D and metabolites in human serum or plasma. Procedure: samples extracted with acetonitrile to release metabolites from binding proteins and remove lipids; extracted samples compete with 125I-labeled 25-OH D3 analog for binding sites on goat anti-25-OH vitamin D primary antibody. Phase separation uses donkey anti-goat, polyethylene glycol precipitating reagent. Radioactivity in precipitate is inversely proportional to 25-OH-D concentration. Used in clinical laboratories by technicians. Results assist clinicians in assessing patient vitamin D sufficiency.

Clinical Evidence

Bench testing and comparative clinical studies performed. Study 1 (n=72): INCSTAR vs HPLC (r=0.993) and INCSTAR vs CPBA (r=0.981). Study 2 (n=106): INCSTAR vs CPBA (r=0.942). Results analyzed via linear regression; demonstrated comparable performance to established CPBA and HPLC methods.

Technological Characteristics

Radioimmunoassay (RIA) utilizing 125I-labeled 25-OH D3 analog. Reagents: goat anti-25-OH vitamin D primary antibody, donkey anti-goat/polyethylene glycol precipitating reagent. Extraction solvent: acetonitrile. Measurement principle: competitive binding with radioactivity detection inversely proportional to analyte concentration.

Indications for Use

Indicated for the quantitative measurement of 25-hydroxyvitamin D and other hydroxylated vitamin D metabolites in human serum or plasma to assess vitamin D sufficiency in patients.

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.

Reference Devices

• CPBA (Competitive Protein Binding Assay) methods
• HPLC (High Pressure Liquid Chromatography) methods

Submission Summary (Full Text)

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K953567

SEP 25 1996

# Attachment 4

# SUMMARY OF SAFETY AND EFFECTIVENESS

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SUMMARY OF SAFETY AND EFFECTIVENESS

DEVICE NAME: INCSTAR 25-Hydroxyvitamin D $^{125}$I RIA

CLASSIFICATION NAME: 25-Hydroxyvitamin D Test System

APPLICANT: INCSTAR Corporation
1990 Industrial Boulevard
Stillwater, MN 55082-0285

DATE: July 26, 1995

The INCSTAR 25-Hydroxyvitamin D $^{125}$I RIA Kit is intended for the quantitative measurement of 25-hydroxyvitamin D and other hydroxylated vitamin D metabolites in human serum or plasma to be used in the assessment of vitamin D sufficiency.

This assay requires serum or plasma samples to be extracted with acetonitrile to free vitamin D and its metabolites which are almost completely associated with binding proteins as well as remove lipids which would interfere with the assay. Calibrators (kit standards) containing known concentrations of 25-hydroxycholecalciferol (25-OH Vitamin D3) in a human serum matrix are likewise extracted. The primary antibody (goat anti-25-OH vitamin D) selected for use in the assay demonstrates high affinity and equal cross-reactivity to both 25(OH)D2 and 25(OH)D3 but very low cross-reactivity to non-hydroxylated vitamin D2 or D3 and 1,25(OH)2 D. The primary antiserum used in the assay does recognize several other dihydroxylated metabolites of vitamin D; however, these metabolites are found in relatively low concentrations in the circulation and are believed to be of minor biological importance. During the assay reaction, samples compete with an $^{125}$I labeled analog of 25-OH D3 for binding sites on the primary antiserum. Phase separation is accomplished using a donkey anti-goat, polyethylene glycol precipitating reagent. The amount of radioactivity contained in the resulting precipitate is inversely proportional to the concentration of 25-OH-D present in the sample.

The INCSTAR 25-Hydroxyvitamin D $^{125}$I RIA Kit has been shown to be substantially equivalent to CPBA and HPLC methods used to determine levels of 25-OH-D. CPBA methods for measuring 25-OH-D have been used by commercial, clinical laboratories prior to the Medical Device Amendments of 1976. Furthermore, both methods have been compared to HPLC and have shown comparable results.

The INCSTAR 25-Hydroxyvitamin D $^{125}$I RIA kit was compared to HPLC (High Pressure Liquid Chromatography), and CPBA (Competitive Protein Binding Assay) 25-OH-D methods. Various patient groups representing a wide range of 25-OH-D values were assayed using the INCSTAR kit, CPBA, and (in one study) HPLC. Results were analyzed using linear regression analysis.

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The first study was performed by two external sites. Each site analyzed 36 serum samples using the INCSTAR kit, HPLC and CPBA. Results from both sites were combined (n=72). Values ranged from 4.7 to 186 ng/mL and gave the following results:

$$
\text{INCSTAR} = 0.954 \, (\text{HPLC}) + 1.327; \text{ correlation coefficient} = 0.993
$$

$$
\text{INCSTAR} = 0.998 \, (\text{CPBA}) - 0.639; \text{ correlation coefficient} = 0.981
$$

The second study, performed by one external site, analyzed 106 serum samples using the INCSTAR kit and CPBA. Results ranged from 7.4 to 461 ng/mL and gave the following results:

$$
\text{INCSTAR} = 1.229 \, (\text{CPBA}) - 5.092; \text{ correlation coefficient} = 0.942
$$