Fig. 1. Linearity of the heparin management test results (standard curve). Data are the mean ± SD (n = 70). Difference within the individual instrument 4% or less; polynomic correlation across the entire range of heparin concentration (cHep) was r²= 0.98; slopes were y = 375 + 49.7 x  (0–3 IU/ml) and y = 375 + 49.7 x  (4–6 IU/ml).