Correlation between turbidimetric and nephelometric methods of measuring C-reactive protein in patients with unstable angina or non-ST elevation acute myocardial infarction

• Main Authors: Luis C. L. Correia, José C. Lima, Gary Gerstenblith, Luis P. Magalhães, Agnaluce Moreira, Octávio Barbosa Jr., Juliana Dumet, Luiz Carlos S. Passos, Argemiro D'Oliveira Júnior, José Péricles Esteves
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Cardiologia (SBC) 2003-08-01
• Series: Arquivos Brasileiros de Cardiologia
• Subjects: C-reactive protein; turbidimetric method; acute coronary syndromes
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0066-782X2003001000002

OBJECTIVE: To evaluate the performance of the turbidimetric method of C-reactive protein (CRP) as a measure of low-grade inflammation in patients admitted with non-ST elevation acute coronary syndromes (ACS). METHODS: Serum samples obtained at hospital arrival from 68 patients (66±11 years, 40 men), admitted with unstable angina or non-ST elevation acute myocardial infarction were used to measure CRP by the methods of nephelometry and turbidimetry. RESULTS: The medians of C-reactive protein by the turbidimetric and nephelometric methods were 0.5 mg/dL and 0.47 mg/dL, respectively. A strong linear association existed between the 2 methods, according to the regression coefficient (b=0.75; 95% C.I.=0.70-0.80) and correlation coefficient (r=0.96; P<0.001). The mean difference between the nephelometric and turbidimetric CRP was 0.02 ± 0.91 mg/dL, and 100% agreement between the methods in the detection of high CRP was observed. CONCLUSION: In patients with non-ST elevation ACS, CRP values obtained by turbidimetry show a strong linear association with the method of nephelometry and perfect agreement in the detection of high CRP.