International Journal of Scientific and Research Publications, Volume 12, Issue 12, December 2022 311 ISSN 2250-3153 This publication is licensed under Creative Commons Attribution CC BY. http://dx.doi.org/10.29322/IJSRP.12.12.2022.p13235 www.ijsrp.org Pre-Analytical Variables In Coagulation Studies Saritha Mary Thomas 1 , Abin Varghese 2 1 Research Scholar, Allied Health Sciences, Srinivas University Mangalore, India 2 Research Scholar, Allied Health Sciences, Srinivas University Mangalore, India DOI: 10.29322/IJSRP.12.12.2022.p13235 http://dx.doi.org/10.29322/IJSRP.12.12.2022.p13235 Paper Received Date: 5 th November 2022 Paper Acceptance Date: 5 th December 2022 Paper Publication Date: 20 th December 2022 Abstract- Background: All coagulation tests critically depend on the quality of the plasma specimens obtained. Pre-analytical variability is a common source of errors in coagulation testing, as clotting assays are susceptible to poor standardization of the whole analytical process. Many misleading results in blood coagulation arise not from errors in testing but from carelessness in the pre- analytical phase. Pre-analytical factors influencing the reliability of laboratory testing are commonplace. Control is critical, since this has a direct influence on the quality of results and their clinical reliability. Internal Quality control should be maintained while performing the tests in the laboratory. Aim: The aim of the study was to evaluate pre-analytical variables that influence the coagulation tests results. Materials and Methods: A sample size of 100 were included in the study. The Pre-analytical variables during the sample collection and processing were analysed as per the proforma. Results: It was found that the entire collection was done by vacutainer system. 83% of the collections were from non-fasting patients. Regarding tourniquet application, all the 100 were collected with tourniquet application. Of that 15 were applied for over one minute and 41% of the samples showed frothing. The tube order (2 nd ) of collection as per the NCCLS guidelines was followed for 96 samples. Mixing was adequate by inverting the tube (8-10) times for most (97%) of the collections. It was found that, the volume was inappropriate for 26 samples. And it was found that the samples were transported to the laboratory from the outpatient sample collection room within the stipulated time. Ninety three out of hundred samples were centrifuged at a speed range of 4000-4500rpm.There was a yield of <10000/ul platelet in the PPP from 44 samples which is the acceptable limit, and the remaining 49 samples had a platelet count in the range10,000-60,000/ul. Of the 49samples, thirty six samples showed a platelet count in the range10,000-20,000/ul,9samples were in between 21,000-40,000/ul and 3 samples in the range of 41000-60000/ul. Among the 49 samples, only 2 samples showed platelet count of 50,000- 60,000 and their PT and aPTT were affected. The occurrence of high platelet count may be due to the variation in the centrifugation speed. It was found that not even a single sample was lysed or clotted. Although, 83% of the collections were from non-fasting patients, the plasma was clear and there was no significant lipemia. It was also found that the three samples high HCT (> 55%) of the sample if not corrected, leads to false prolongation of the results. The time lapse between the sample collection and the report despatch was analysed and found that for 92 out of 100 samples, the turnaround time was within the acceptable limits as defined by the laboratory. Conclusion: Among the pre-analytical variables analysed in the study, tourniquet application, duration of application, order of draw, method of collection and mixing and centrifugation duration were found to be well under control. A better control is required in centrifugation speed to obtain PPP where the platelet count is less than 10000/ul. Index Terms- Pre-analytical variables, Coagulation, Haemostasis, Icteric, Lipemic, Haemolysis I. INTRODUCTION aemostasis is a host defence mechanism that protects the integrity of the vascular system after tissue injury. The mechanism has several important functions. It helps to maintain blood in a fluid state while it remains circulating within the vascular system, to arrest bleeding at the site of injury / bleeding loss by formation of a hemostatic plug and to ensure eventual removal of plug when heading is complete.[1] There are five different components of haemostatic mechanism  Blood Vessels  Platelets  Plasma coagulation factors  Inhibitors  Fibrinolytic system [2] Any defect in the haemostatic mechanism can lead to excessive bleeding or thrombosis. Thrombosis occurs when the endothelial lining of blood vessels is damages or removed. The processes include coagulation and platelet aggregation that cause formation and dissolution of platelet aggregation.[3] There are four phases for haemostasis: (i) Constriction of the injured blood vessel to diminish blood flow. (i) Formation of a loose and temporary platelet aggregate at the site of injury, platelets bind to collagen and are activated by thrombin. After the activation, platelets change their shape and in presence of fibrinogen, aggregate to form haemostatic plug in haemostasis or thrombus in thrombosis. H