A quantitative C-reactive protein assay using latex agglutination in microtiter plates.

In this quantitative assay, latex particles coated with anti-C-reactive protein (CRP) are agglutinated by CRP following vortex agitation in microtiter plates. A decrease in absorbance at 405 nm is directly proportional to CRP concentration. This 30 min assay is simple and necessitates only two pipetting steps after serum dilution. The linear part of the standard curve ranges from 5 to 150 mg/l and CRP concentrations up to 300 mg/l can be determined without additional dilution of sera. Within-assay reproducibility varies from 4.4% to 7.5% while between-assay reproducibility ranges from 9.3% to 12.2%. Correlation studies performed with 104 sera assayed by automated nephelometer and turbidimeter gave correlation coefficients of 0.96 and 0.97 respectively.

Home blood glucose monitoring, glycosylated hemoglobin and fructosamine: their relationships in diabetic patients with and without residual C-peptide secretion.

HbA1c and fructosamine (F) were determined at monthly intervals in insulin-treated diabetic outpatients with (n = 25; C-peptide [+]) and without (n = 30; C-peptide [-]) residual B-cell function (post-prandial C-peptide: 0.76 +/- 0.33 and less than or equal to 0.09 pmol/ml, respectively; mean +/- SD), performing home blood glucose monitoring (HBGM) (40 determinations/month; memory containing reflectometer) during 4 months. Mean monthly blood glucose did not change with time and was equivalent in both groups (9.3 +/- 3.3 and 9.4 +/- 2.0 mmol/l). The magnitude of glycemic excursions was lower in C-peptide [+] than C-peptide [-] patients (mean intra-individual coefficients of variation: 31% and 47%, respectively; P less than 0.001). Overall mean HbA1c was of 7.12 +/- 1.32 and 7.30 +/- 1.06% and F levels were of 44 +/- 6 and 48 +/- 7 mumol/g protein (P less than 0.001) in the C-peptide [+] and [-] groups, respectively. In C-peptide [+] patients, HbA1c strongly correlated with prior mean monthly blood glucose at all visits (range of r valeurs = 0.71-0.84; P less than 0.001); the relation between F and mean monthly blood glucose was always significant but weaker (r = 0.48-0.62; P less than 0.05-0.001). In C-peptide [-] patients, HbA1c correlated weakly with mean blood glucose, only when averaged over 8 weeks (r = 0.40-0.59; P less than 0.05-0.001) but F did not correlate with blood glucose, whether averaged over 1-8 week periods.(ABSTRACT TRUNCATED AT 250 WORDS)