Elecsys Vitamin D total II

Catalog Number: 07464215160

SYSTEM INFORMATION

INTENDED USE

The Elecsys Vitamin D total II assay is intended for the quantitative determination of total 25‑hydroxyvitamin D in human serum and plasma. This assay is to be used as an aid in the assessment of vitamin D sufficiency in adults.

RESULTS ARE DETERMINED VIA A CALIBRATION CURVE WHICH IS INSTRUMENT-SPECIFICALLY GENERATED BY 2‑POINT CALIBRATION AND A MASTER CURVE PROVIDED VIA THE REAGENT BARCODE OR E‑BARCODE.

STORAGE AND STABILITY

Store at 2‑8 °C.

CRITERION: METHOD COMPARISON SERUM VERSUS PLASMA, SLOPE 0.9‑1.1 + INTERCEPT WITHIN ≤ 3 NG/ML + COEFFICIENT OF CORRELATION ≥ 0.95.

A comparison of the Elecsys Vitamin D total II assay (y) using the CDC Verification Samples with concentrations assigned by the CDC Vitamin D Reference Laboratory by ID‑LC‑MS/MS (x) gave the following correlations (ng/mL):

CALIBRATION

Traceability: This method is traceable to internal reference standards which are traceable to the ID‑LC‑MS/MS 25‑hydroxyvitamin D Reference Measurement Procedure.18,19 The ID‑LC‑MS/MS is traceable to the National Institute of Standards and Technology Standard Reference Material 2972.20

EVERY ELECSYS REAGENT SET HAS A BARCODED LABEL CONTAINING SPECIFIC INFORMATION FOR CALIBRATION OF THE PARTICULAR REAGENT LOT. THE PREDEFINED MASTER CURVE IS ADAPTED TO THE ANALYZER USING THE RELEVANT CALSET.

CALIBRATION MUST BE PERFORMED ONCE PER REAGENT LOT USING FRESH REAGENT (I.E. NOT MORE THAN 24 HOURS SINCE THE REAGENT KIT WAS REGISTERED ON THE ANALYZER).

CALIBRATION INTERVAL MAY BE EXTENDED BASED ON ACCEPTABLE VERIFICATION OF CALIBRATION BY THE LABORATORY.

RENEWED CALIBRATION IS RECOMMENDED AS FOLLOWS:

CONTROLS FOR THE VARIOUS CONCENTRATION RANGES SHOULD BE RUN INDIVIDUALLY AT LEAST ONCE EVERY 24 HOURS WHEN THE TEST IS IN USE, ONCE PER REAGENT KIT, AND FOLLOWING EACH CALIBRATION.

LIMITS AND RANGES

Measuring range

MEASURING RANGE

5‑100 ng/mL or 12.5‑250 nmol/L (defined by the Limit of Quantitation and the maximum of the master curve). Values below the Limit of Quantitation are reported as < 5 ng/mL (< 12.5 nmol/L). Values above the measuring range are reported as > 100 ng/mL (> 250 nmol/L).

5‑100 NG/ML OR 12.5‑250 NMOL/L (DEFINED BY THE LIMIT OF QUANTITATION AND THE MAXIMUM OF THE MASTER CURVE). VALUES BELOW THE LIMIT OF QUANTITATION ARE REPORTED AS < 5 NG/ML (< 12.5 NMOL/L). VALUES ABOVE THE MEASURING RANGE ARE REPORTED AS > 100 NG/ML (> 250 NMOL/L).

LOWER LIMITS OF MEASUREMENT

Limit of Blank, Limit of Detection and Limit of Quantitation

SAMPLES WITH 25‑HYDROXYVITAMIN D CONCENTRATIONS ABOVE THE MEASURING RANGE CAN BE DILUTED WITH DILUENT UNIVERSAL OR A SUITABLE HUMAN SERUM WITH A LOW ANALYTE CONCENTRATION. THE RECOMMENDED DILUTION IS 1:2. THE CONCENTRATION OF THE DILUTED SAMPLE MUST BE ≥ 40  NG/ML (≥ 100 NMOL/L).

SPECIFIC PERFORMANCE DATA

Representative performance data on the analyzers are given below.Results obtained in individual laboratories may differ.

PRECISION

Precision was determined using Elecsys reagents, samples and controls in a protocol (EP05‑A3) of the CLSI (Clinical and Laboratory Standards Institute): 2 runs per day in duplicate each for 21 days (n = 84). The following results were obtained:

PRECISION WAS DETERMINED USING ELECSYS REAGENTS, SAMPLES AND CONTROLS IN A PROTOCOL (EP05‑A3) OF THE CLSI (CLINICAL AND LABORATORY STANDARDS INSTITUTE): 2 RUNS PER DAY IN DUPLICATE EACH FOR 21 DAYS (N = 84). THE FOLLOWING RESULTS WERE OBTAINED:

INTERMEDIATE PRECISION

INTERMEDIATE PRECISION

METHOD COMPARISON

A comparison of the Elecsys Vitamin D total II assay (y) using the CDC Verification Samples with concentrations assigned by the CDC Vitamin D Reference Laboratory by ID‑LC‑MS/MS (x) gave the following correlations (ng/mL):

ANALYTICAL SPECIFICITY

A study was performed based on guidance from CLSI EP07‑A2 to evaluate the cross‑reactivity of the assay with other vitamin D metabolites. Samples containing the cross‑reactants were prepared at three 25‑hydroxyvitamin D concentrations (25, 40 and 60 ng/mL). The % cross‑reactivity was calculated for each sample using the equation below and normalized to the cross‑reactivity of 25 hydroxyvitamin D3.30

BABLOK W, PASSING H, BENDER R, ET AL. A GENERAL REGRESSION PROCEDURE FOR METHOD TRANSFORMATION. APPLICATION OF LINEAR REGRESSION PROCEDURES FOR METHOD COMPARISON STUDIES IN CLINICAL CHEMISTRY, PART III. J CLIN CHEM CLIN BIOCHEM 1988 NOV;26(11):783-790.