Significantly different coagulation factor activities underlying the variability of 'normal' activated partial thromboplastin time.
The activated partial thromboplastin time (aPTT) is a widely used coagulation screening test in routine laboratories. The aPTT level in the control population varies and is reflected by the reference interval. However, there have been no studies to investigate the coagulation status determining the variability of the aPTT. The aim of this study was to investigate the coagulation factor activities underlying the variability of aPTT in the population. The study participants were reference individuals with prothrombin time and aPTT within reference intervals. The aPTT was determined using STA-PTT Automate (Diagnostica Stago, Asnieres, France; local reference interval, 29.1-41.9 s). Those with aPTT within the marginal ranges of reference interval were selected for factor assays. We defined the lower marginal group as the lowest 10 percentile of reference interval (29.1-30.9 s) and the upper marginal group as the highest 10 percentile (38.0-41.9 s). Activities of factor II, V, VIII, IX, X, XI, and XII were determined in both groups. The lower marginal and upper marginal groups consisted of 220 and 209 individuals, respectively. All coagulation factors were significantly higher in the lower marginal than in the upper marginal group (P = 0.0127 for factor II and P < 0.0001 for the others). Multiple logistic regression analyses revealed factor XII and VIII were two strongest contributors determining the aPTT level, whereas factor XI was not significantly different between the groups (P = 0.095). This study firstly demonstrated significantly different coagulation factor activities underlying the variability of aPTT in reference individuals. The results suggested the possibility of disease association or phenotypic contribution of variable coagulation activities in the population.
Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Kyoung-Jin
KJ
Park
Eui-Hoon
EH
Kwon
Youngeun
Y
Ma
In-Ae
IA
Park
Seon-Woo
SW
Kim
Sun-Hee
SH
Kim
Hee-Jin
HJ
Kim
D001778:Blood Coagulation Disorders / Q000097:blood / Q000235:genetics*; D001779:Blood Coagulation Factors / Q000032:analysis*; D001780:Blood Coagulation Tests / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time / Q000379:methods*; D011110:Polymorphism, Genetic; D012016:Reference Values
D001779:Blood Coagulation Factors