[Determination of C-reactive protein (CRP) in capillary blood--a comparison with the CPR level in venous serum].
C-reactive protein (CRP) has served as a reliable indicator of infectious and inflammatory diseases for a long time. Sequential CRP determinations offer a useful means of monitoring clinical courses and therapeutic effects in patients of any age as its serum concentrations correlate well with clinical symptoms. Especially in pediatric patients, however, venous blood sampling causes many problems. Thus, in our study a new method of CRP analysis from capillary plasma samples was tested and compared with CRP determinations from venous serum samples. 101 pairs of samples simultaneously obtained from 64 pediatric and neonatal patients (mean age of 5.8 months: min. 1 day, max. 5.5 years) were analyzed and compared. A good correlation (r = 0.967) was found for the whole range of measured CRP-concentrations (5-175 mg/l), showing a linear relationship between both methods. Results were analyzed by chi 2-test. Using a cutoff level of 5 mg/l, a sensitivity of 96%, a specificity and a positive predictive value of 98% each and an efficiency of 97% was found. Thus, the CRP determination from capillary blood samples offers a reliable method and a useful alternative for conventional analysis from venous serum.