HCYS

Catalog Number: 05385415190

SYSTEM INFORMATION

For cobas c 311/501 analyzers:

HCYS: ACN 778

For cobas c 502 analyzer:

HCYS: ACN 8778

INTENDED USE

In vitro test for the quantitative determination of total L-homocysteine in human serum and plasma on Roche/Hitachi cobas c systems. The assay can assist in the diagnosis of patients suspected of having hyperhomocysteinemia or homocystinuria.

STORAGE AND STABILITY

HCYS
Shelf life at 2-8 °C: See expiration date on cobas c pack label.
On-board in use and refrigerated on the analyzer: 4 weeks
Diluent NaCl 9 %
Shelf life at 2-8 °C: See expiration date on cobas c pack label.
On-board in use and refrigerated on the analyzer: 12 weeks

Do not freeze.

APPLICATION FOR SERUM AND PLASMA

cobas c 311 test definition
Assay type 2-Point End
Reaction time / Assay points 10 / 36-57
Wavelength (sub/main) 700/340 nm
Reaction direction Decrease
Units µmol/L
Reagent pipetting Diluent (H2O)
R1 176 µL
R2 28 µL
R3 20 µL
Sample volumes Sample Sample dilution
Sample Diluent (NaCl)
Normal 14 µL
Decreased 14 µL 30 µL 120 µL
Increased 14 µL

cobas c 501/502 test definition
Assay type 2-Point End
Reaction time / Assay points 10 / 51-70
Wavelength (sub/main) 700/340 nm
Reaction direction Decrease
Units µmol/L
Reagent pipetting Diluent (H2O)
R1 176 µL
R2 28 µL
R3 20 µL

Sample volumes Sample Sample dilution
Sample Diluent (NaCl)
Normal 14 µL
Decreased 14 µL 30 µL 120 µL
Increased 14 µL

CALIBRATION

Traceability: This method has been standardized against NIST SRM 1955 reference material.

Calibrators S1-5: HCYS Calibrator Kit
Multiply the lot-specific HCYS Calibrator Kit calibrator value by the factors below to determine the standard concentrations for the 5-point calibration curve:
S1: 0.050 S4: 0.500
S2: 0.100 S5: 1.00
S3: 0.250
Calibration mode RCM
Calibration frequency Full calibrationevery 7 daysafter reagent lot change as required following quality control procedures

LIMITS AND RANGES

Measuring range

3–50 µmol/L

Determine samples having higher concentrations via the rerun function. Dilution of samples via the rerun function is a 1:5 dilution. Results from samples diluted using the rerun function are automatically multiplied by a factor of 5.

Lower limits of measurement

Limit of Blank (LoB) and Limit of Detection (LoD)

Results for LoB and LoD were determined on the cobas c 501 analyzer and met the predetermined specifications of £ 3 µmol/L for both LoB and LoD.

The Limit of Blank and Limit of Detection were determined in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP17-A requirements.

The Limit of Blank is the 95th percentile value from n ³ 60 measurements of analyte-free samples over several independent series. The Limit of Blank corresponds to the concentration below which analyte-free samples are found with a probability of 95 %.

The Limit of Detection is determined based on the Limit of Blank and the standard deviation of low concentration samples.

The Limit of Detection corresponds to the lowest analyte concentration which can be detected (value above the Limit of Blank with a probability of 95 %).

SPECIFIC PERFORMANCE DATA

Representative performance data on the cobas c 501 analyzers are given below. Results obtained in individual laboratories may differ.

PRECISION

Repeatability and intermediate precision were determined using human samples and controls in accordance with the CLSI (Clinical and Laboratory Standards Institute) EP5 requirements (2 aliquots per run, 2 runs per day, 21 days). The following results were obtained:

Repeatability Meanµmol/L SDµmol/L CV%
Homocysteine Control 1 12.2 0.2 1.5
Homocysteine Control 2 39.1 0.7 1.8
Human serum 1 8.26 0.16 2.0
Human serum 2 13.1 0.2 1.8
Human serum 3 30.0 0.4 1.4
Human serum 4 44.4 0.9 2.0

Intermediate precision Meanµmol/L SDµmol/L CV%
Homocysteine Control 1 12.2 0.3 2.1
Homocysteine Control 2 39.1 0.8 2.0
Human serum 1 8.26 0.19 2.3
Human serum 2 13.1 0.3 2.1
Human serum 3 30.0 0.5 1.8
Human serum 4 44.4 1.0 2.2

METHOD COMPARISON

Hcy values for human serum samples obtained on the cobas c 501 analyzer (y) were compared to those determined with Diazyme reagent on a COBAS INTEGRA 400 analyzer (x).

Sample size (n) = 102

Passing/Bablok11 Linear regression
y = 0.999x - 0.696 µmol/L y = 0.997x - 0.571 µmol/L
t = 0.959 r = 0.996
The sample concentrations were between 4.76 and 46.59 µmol/L.