Comparison and evaluation of two C-reactive protein assays based on particle-enhanced immunoturbidimetry

The use of C-reactive protein (CRP) assays is increasing for a wide range of clinical conditions, and consequently the analytical performance requirements for CRP assays are also changing. For this reason, manufacturers have been developing CRP assays based on different methodologies to provide both high sensitivity and a wide measuring range. However, it is questionable whether these methods can meet the desired requirements for CRP assays. CRP Latex on the Cobas Integra 400 and CRP Tina-quant Latex on the Modular Analytics-P were evaluated in terms of detection limit, linearity, intra- and interassay precision, and comparability with 268 patient samples. The intra- and interassay precision of the two methods was 10% in the pool with concentrations of similar to 0.60 mg/L. The detection limits for CRP Latex and Tina-quant Latex were 0.20 and 0.22 mg/L, respectively. Both methods were linear up to 215 mg/L. There was a good agreement between the two assays, except for a scattering at concentrations near the detection limits. Deming regression analysis for CRP Latex (x-axis) and Tina-quant Latex (y-axis) yielded a slope of 1.067 +/- 0.018, an intercept of -0.148 +/- 0.358, and an S-ylx of 5.10 (r=0.996, P < 0.0001). The two assays gave comparable results. Low precision was determined for both assays, except for the low pool with a concentration of similar to 0.60 mg/L. We concluded that both of these assays should be improved to meet high-sensitivity criteria

Plasma thiobarbituric acid-reactive substance levels in subclinical hypothyroidism.

Objective: The purpose of this study was to determine thiobarbituric acid-reactive substance (TBARS) levels in subclinical hypothyroidism and to examine the effect of levothyroxine replacement on TBARS levels. Subjects and Methods: A cohort of 28 female patients with subclinical hypothyroidism and 24 healthy controls were enrolled in this study. The levels of plasma TBARS, serum lipids, and high-sensitive C-reactive protein (CRP) in patients with subclinical hypothyroidism at baseline and after achieving euthyroid state by levothyroxine were assessed. Results: TBARS levels of the patients were similar to those of the control group in the subclinical hypothyroid state and after restoration of euthyroidism by levothyroxine replacement. TBARS levels decreased after levothyroxine treatment, but did not reach statistical significance. There was no significant correlation between TBARS, lipid and CRP levels. Serum CRP levels were higher in subclinical hypothyroidism (4.28 +/- 0.9 mg/l) than in the control group (1.95 +/- 0.34 mg/l) and the difference was statistically significant (p = 0.03). After achieving euthyroid state, CRP levels decreased significantly in patients with subclinical hypothyroidism from 4.28 +/- 0.9 to 2.32 +/- 0.6 mg/l (p = 0.006). Conclusion: Our findings suggest that there is no significant alteration of plasma TBARS levels neither in subclinical hypothyroid state nor after achieving euthyroid state. Serum CRP level is higher in patients with subclinical hypothyroidism than in the control group. Normalization of thyroid state seems to effectively reduce serum CRP levels in subclinical hypothyroidism without any correlation with TBARS activity. Copyright (C) 2007 S. Karger AG, Basel