Cardiac C-Reactive Protein (Latex) High Sensitive

Catalog Number: 05950864190




In vitro test for the quantitative determination of C-reactive protein (CRP) in human serum and plasma on Roche/Hitachi cobas c systems. Measurement of CRP is of use for the detection and evaluation of inflammatory disorders and associated diseases, infection and tissue injury. Highly sensitive measurement of CRP may also be used as an aid in the assessment of the risk of future coronary heart disease. When used as an adjunct to other laboratory evaluation methods of acute coronary syndromes, it may also be an additional independent indicator of recurrent event prognosis in patients with stable coronary disease or acute coronary syndrome.


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
On-board on the Reagent Manager: 24 hours
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: 4 weeks
On-board on the Reagent Manager: 24 hours


cobas c 701/702 test definition
Assay type Rate A
Reaction time / Assay points 10 / 22-38
Wavelength (sub/main) – /546 nm
Reaction direction Increase
Units mg/L (nmol/L, mg/dL)
Reagent pipetting Diluent (H2O)
R1 82 µL 42 µL
R3 28 µL 20 µL
Sample volumes Sample Sample dilution
Sample Diluent (NaCl)
Normal 6 µL
Decreased 6 µL 10 µL 140 µL
Increased 12 µL


Traceability: This method has been standardized against the reference preparation of the IRMM (Institute for Reference Materials and Measurements) BCR470/CRM470 (RPPHS - Reference Preparation for Proteins in Human Serum).25

Calibrators S1: H2OS2-S6: C.f.a.s. Proteins
Multiply the lot-specific C.f.a.s. Proteins calibrator value by the factors below to determine the standard concentrations for the 6-point calibration curve:
S2: 0.0125 S5: 0.100
S3: 0.0250 S6: 0.200
S4: 0.0500
Calibration mode Line Graph
Calibration frequency Full calibrationafter reagent lot change as required following quality control procedures


Measuring range

0.15-20.0 mg/L (1.43-190 nmol/L, 0.015-2.0 mg/dL)

Determine samples having higher concentrations via the rerun function. Dilution of samples via the rerun function is a 1:15 dilution. Results from samples diluted by the rerun function are automatically multiplied by a factor of 15.

Lower limits of measurement

Lower detection limit of the test

0.15 mg/L (1.43 nmol/L, 0.015 mg/dL)

The lower detection limit represents the lowest measurable analyte level that can be distinguished from zero. It is calculated as the value lying 3 standard deviations above that of the lowest standard (standard 1 + 3 SD, repeatability, n = 21).

Values below the lower detection limit (< 0.15 mg/L) will not be flagged by the instrument.

Functional sensitivity

0.3 mg/L (2.96 nmol/L, 0.03 mg/dL)

The functional sensitivity is the lowest CRP concentration that can be reproducibly measured with an inter-assay coefficient of variation of < 10 %.


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


Precision was determined using human samples and controls in an internal protocol with repeatability (n = 21) and intermediate precision (3 aliquots per run, 1 run per day, 21 days). The following results were obtained:

Results for intermediate precision were obtained on the master system cobas c 501 analyzer.

Repeatability Meanmg/L (nmol/L, mg/dL) SDmg/L (nmol/L, mg/dL) CV%
Precinorm Protein 14.0 (133, 1.40) 0.1 (0.952, 0.010) 0.3
CRP T Control N 4.13 (39.3, 0.413) 0.04 (0.381, 0.004) 1.0
Human serum A 6.58 (62.6, 0.658) 0.05 (0.476, 0.005) 0.7
Human serum B 13.0 (124, 1.30) 0.1 (0.952, 0.010) 0.7
Human serum C 0.511 (4.86, 0.051) 0.012 (0.114, 0.001) 2.3

Intermediate precision Meanmg/L (nmol/L, mg/dL) SDmg/L (nmol/L, mg/dL) CV%
Precinorm Protein 9.06 (86.3, 0.906) 0.11 (1.1, 0.011) 1.3
CRP T Control N 4.28 (40.8, 0.428) 0.11 (1.1, 0.011) 2.6
Human serum 3 13.3 (126, 1.33) 0.3 (3, 0.03) 2.1
Human serum 4 0.53 (5.05, 0.053) 0.05 (0.48, 0.005) 8.4


CRP values for human serum and plasma samples obtained on a Roche/Hitachi cobas c 701 analyzer (y) were compared to those determined with the corresponding reagent on a Roche/Hitachi cobas c 501 analyzer (x).

Sample size (n) = 231

Passing/Bablok33 Linear regression
y = 0.996x - 0.074 mg/L y = 0.998x - 0.079 mg/L
t = 0.987 r = 1.000
The sample concentrations were between 0.180 and 17.8 mg/L (1.71 and 169 nmol/L, 0.018 and 1.78 mg/dL).