Salicylate

Catalog Number: 20753580322

SYSTEM INFORMATION

Test SALI, test ID 0-158.

INTENDED USE

In vitro diagnostic test for the quantitative determination of toxic levels of salicylate in serum or heparinized plasma on COBAS INTEGRA systems.

STORAGE AND STABILITY

Shelf life at 2-8 °C See expiration date on cobas c pack label
COBAS INTEGRA 400 plus system
On-board in use at 10-15 °C 12 weeks
COBAS INTEGRA 800 system
On-board in use at 8 °C 26 weeks

The on-board in use stability period begins at the time of cobas c pack puncture.

APPLICATION FOR SERUM AND PLASMA

Measuring mode Absorbance
Abs. calculation mode Endpoint
Reaction mode R1-S-SR
Reaction direction Decrease
Wavelength A 340 nm
Calc. first/last 33/64
Unit µg/mL

COBAS INTEGRA 400 plus test definition

PIPETTING PARAMETERS

Diluent (H2O)
R1 100 µL 10 µL
Sample 2.5 µL 20 µL
SR 5 µL 10 µL
Total volume 147.5 µL

Diluent (H2O)
R1 100 µL 10 µL
Sample 2.5 µL 20 µL
SR 5 µL 10 µL
Total volume 147.5 µL

COBAS INTEGRA 800 TEST DEFINITION

Measuring mode Absorbance
Abs. calculation mode Endpoint
Reaction mode R1-S-SR
Reaction direction Decrease
Wavelength A 340 nm
Calc. first/last 44/98
Unit µg/mL

PIPETTING PARAMETERS

Diluent (H2O)
R1 100 µL 10 µL
Sample 2.5 µL 20 µL
SR 5 µL 10 µL
Total volume 147.5 µL

CALIBRATION

A calibration curve must be prepared using the COBAS Salicylate Calibrators. Calibrators must be placed from the higher concentration (B) first, to the lower (A) last, on the CAL/QC rack. This curve is retained in memory by the COBAS INTEGRA systems and recalled for later use.

Traceability: The COBAS Salicylate Calibrators are prepared to contain known quantities of salicylate in normal human serum and are traceable to USP reference standards.

Note

Calibrators should be assayed within 2 hours after placing on-board the instrument.

Calibrators COBAS Salicylate Calibrators
Calibrators A-B
Calibration mode Linear regression
Calibration replicate Duplicate recommended
Calibration interval Each lot, every 26 weeks, and as required following quality control procedures

LIMITS AND RANGES

Measuring range

COBAS INTEGRA 400 plus analyzer:

1.35-700 µg/mL  (0.01-5.07 mmol/L)

COBAS INTEGRA 800 analyzer:

2.6-700 µg/mL  (0.02-5.07 mmol/L)

Lower limits of measurement

Lower detection limit of the test:

COBAS INTEGRA 400 plus analyzer:

1.35 µg/mL  (0.01 mmol/L)

COBAS INTEGRA 800 analyzer:

2.6 µg/mL  (0.02 mmol/L)

The lower detection limit represents the lowest measurable analyte level that can be distinguished from the zero calibrator at a 95 % confidence level.

SPECIFIC PERFORMANCE DATA

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

PRECISION

Precision was determined using controls in accordance with the NCCLS EP5-T28 requirements with repeatability and intermediate precision (2 aliquots per run, 2 runs per day, 20 days). The following results were obtained on a COBAS INTEGRA 700 analyzer:

Repeatability Meanµg/mL (mmol/L) SDµg/mL(mmol/L) CV%
Level 1 33.5 (0.243) 1.8 (0.013) 5.2
Level 2 180 (1.30) 2 (0.014) 1.3
Level 3 479 (3.47) 5 (0.036) 1.0

Intermediate precision Meanµg/mL (mmol/L) SDµg/mL(mmol/L) CV%
Level 1 33.5 (0.243) 2.2 (0.016) 6.4
Level 2 180 (1.30) 3 (0.022) 1.5
Level 3 479 (3.47) 6 (0.043) 1.3

METHOD COMPARISON

Salicylate values for human serum samples obtained on a COBAS INTEGRA 700 analyzer using the COBAS INTEGRA Salicylate reagent (y) were compared with those determined using a commercially available FPIA method (x).

FPIA
Number of samples 131
Range of values min. 0.0 µg/mL
max. 436.2 µg/mL
Slope 0.943
Intercept 4.725 µg/mL
Correlation coefficient 0.957

ANALYTICAL SPECIFICITY

The following cross-reactive, structurally related and/or co-administered substances were evaluated on the COBAS INTEGRA systems in normal human serum spiked with salicylate at 300 µg/mL (2.17 mmol/L). Each substance was tested at 10 times the highest concentration for its therapeutic or normal range, as per the protocol described by NCCLS.9 The imprecision of the assay was taken into account when determining cross-reactivity. Cross-reactivity was designated as “not detectable” (ND) if the obtained value was less than the sensitivity of the assay.

ND = Not Detectable

Any modification of the instrument as set forth in this labeling requires validation by the laboratory.

Cross-reactivity (%) = 100 × (analytical result - analyte concentration)
concentration of interferent

Drug Level testedµg/mL Cross-reactivity%
Acetaminophen 500 ND
Acetylsalicylic acid 1000 1.6
m-Aminosalicylate 1000 21.1
p-Aminosalicylate 1000 61.4
p-Anisic acid 1000 ND
Benzoic acid 1000 0.1
Chlorzoxazone 500 ND
Diflunisal 500 2.6
EDTA disodium 300 ND
Gentisic acid 1000 8.4
Homogentisic acid 1000 14.5
Salicyluric acid 1000 ND
Ibuprofen 500 ND
alpha-Ketobutyric acid 1000 ND
Methyl salicylate 1000 40.9
Naprosyn (Naproxen) 500 ND
Oxalic acid 300 ND
Phenol 1000 ND
Salicylamide 1000 ND
Theophylline 300 ND
Uric acid 300 ND