Effect of some preanalytical variables on some screening tests of coagulation : a single center experience

Background Preanalytical circumstances are significant in laboratory assessment. Prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen (Fbg), measurements are basic coagulation tests used to evaluate variations of coagulation systems. Aim Investigate to what extent the storage temperature and time influence the results of routine coagulation tests (PT, APTT, and Fbg). It included a total of 120 participants were assayed for different storage temperatures. Patients and methods The platelet poor plasma was assayed for baseline values for PT, APTT, and Fbg on Sysmex 1500 apparatus, and then it was assayed for different storage temperature and time. Results The PT results showed no significant difference when compared with the baseline when samples were kept at 4°C for 12 h storage and at −20°C for 12 h. The APTT results showed significant difference when compared with the baseline at all temperatures. The Fbg results showed no significant difference when compared with the baseline when the sample were kept at 4 and −20°C for 24 h. Conclusion It is not recommended that the PT samples in normal persons be stored at room temperature but can be stored at 4 or −20°C for 12 h. APTT samples in normal persons cannot be stored up to 12 h at any temperature. Fbg samples in normal persons cannot be stored up to 24 h at any temperature. So estimation of APTT and Fbg must be done as early as possible.