Fig. 2. Relation between the heparin management test measurement and heparin concentration (cHep) at selective variations of hematocrit (n = 210;A ), platelets (n = 210;B ), and procoagulants (n = 210;C ). Data are the mean ± SD. (A ) Correlation (r²) between the test and the calibration curve was 0.99 over hematocrit 20 and 30%, and 0.98 at hematocrit 60% (values at hematocrit 60% significantly differed [P < 0.05] from hematocrit 20%). (B ) During dilution of platelets but with constant hematocrit and plasma protein, correlation was 0.99, and values were not significantly different. (C ) At different plasma protein contents but constant hematocrit and platelets, correlation was 0.98 (values at 10% dilution significantly differed [P < 0.01] from values over 50 and 30%). (A–C ) Within-instrument difference of measurements was 4% or less (variation between the values obtained in the five volunteers averaged 15%).