Immulite 2000 nt probnp

Plasma concentrations of cTnI and NT-proBNP were measured by radioimmunoassay (ADVIA Centaur TnI-Ultra Assay, Siemens; IMMULITE 2000 NT-proBNP, Siemens). cTnI was considered positive for values >6 ng/L and significantly elevated at a level >40 ng/L (99th percentile). NT-proBNP was considered positive at a level of >125 pg/ml.

Blood was collected after overnight fasting to determine blood cell counts, ESR, serum concentration of CRP, creatinine (Cr), uric acid, glucose, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) at the central laboratory of University Hospital. CRP was measured by immunoturbidimetric assay (upper limit 5 mg/l). Concentrations of TC, HDL-C, TG were measured with standard enzymatic technique (BIOMAXIMA); LDL-C was calculated according to Friedewald formula. Atherogenic index (AI) calculated as ratio TC/HDL-C seems to be more appropriate to assess CV risk in RA than individual cholesterol fractions (normal AI: <4.0 in women and <4.5 in men) [19 (link)].
Serum samples were stored at −80^o C for further assessment of NT-pro-BNP. Measurement of NT-proBNP concentration was performed using chemiluminescent immunometric assay (IMMULITE 2000 NT-proBNP, Siemens). Reference range according to manufacturer’s guidelines is up to 125 pg/ml in patients <75 years and up to 450 pg/ml in older; analytical sensitivity 10 pg/ml. BNP and NT-proBNP levels ≥100 pg/ml are significantly related to cardiac morbidity and mortality [12 (link)].