Measurement of C‐reactive protein: Two high sensitivity methods compared

Abstract

C-reactive protein (CRP) is an acute phase marker and a predictor of the risk of developing atherosclerotic complications. However, as a predictor of this risk, high sensitivity measurements are needed, and high sensitive CRP (hsCRP) assays have been developed. In this study, we experimentally compared two hsCRP assays, based on nephelometry and turbidimetry, both implemented on automated analyzers. Linearity, imprecision, turbidity interference, and results in the assay of 96 samples have been compared. Method comparison of the same two analytical systems in the assay of CRP was also performed on the basis of results in an interlaboratory external quality assessment scheme (EQAS). The two systems were found to perform substantially equally, both in hsCRP and in CRP measurement, but in the hsCRP assay the precision of nephelometry (CV% in the interval 3.0-5.8) was lower than that of turbidimetry (CV% in the interval 1.8-2.3). The classification of results by the two methods into three predefined relative risk classes gave 18% rate of discordance, in any case by one class only. The two methods proved reliable and comparable in the measurement of hsCRP, but precision should be improved.

A new turbidimetric method for assaying serum C-reactive protein based on phosphocholine interaction

“…The observed imprecision CV of the described functional CRP assay exceeds the one described for the immunoturbidimetric assay (27). However, the functional CRP assay fulfills the imprecision criteria based on the biological variability of the analyte (28).…”

Vitamin B6 supplementation improves pro-inflammatory responses in patients with rheumatoid arthritis

“…Serum folate was analyzed by using standard competitive immunochemiluminometric methods on a Chiron Diagnostics ACS: 180 Automated Chemiluminescence System (Chiron Diagnostics Corporation, East Walpole, MA, USA). Automated highsensitivity CRP (hs-CRP) measurement was performed using particle-enhanced immunonephelometry with an image analyzer (Dominici et al, 2004). The cut-off value of hs-CRP was set at 0.3 mg per 100 ml.…”

Metabolic syndrome and growth hormone deficiency in adult survivors of childhood acute lymphoblastic leukemia

“…Circulating blood levels of creatinine and C-reactive protein were measured with rate nephelometry 31 ; insulin, insulin-like growth factor I (IGF-I), thyroxine, and thyroid-stimulating hormone with chemiluminescent immunoassays 32 ; and homocysteine with fluorescence polarization immunoassays. 33 The homeostasis model assessment of insulin resistance index (HOMA) was calculated from fasting plasma insulin and glucose values as described by Matthews et al 34 Waist circumference was measured between the anterior superior iliac spine and the lower rib margin.…”