Effect of Higher Centrifugation Speed and Shortened Centrifugation Time on Prothrombin and Activated Thromboplastin Time

Effect of centrifugation on coagulation tests
Vol. 6 No. 1 : 2011 (68-72)

Azlin I Azlin I
Hafiza A Hafiza A
Azma RZ Azma RZ
Aidifitrina RK Aidifitrina RK
Hamidah NH Hamidah NH

Abstract
Centrifugation of blood samples to produce platelet-poor plasma is one of the important steps for coagulation testing. Reduction of the time required for specimen processing without affecting quality of results should be ideal for tests which require immediate results. Centrifugation of platelet-poor plasma (3580 rpm) for 15 minutes performed for routine coagulation tests would prolong the turn-around time for an urgent test (30 minutes). This study was done to determine the effect of reducing centrifugation time for routine coagulation tests in order to meet the turn-around time (TAT) for urgent tests. Seventy-nine blood samples sent for routine coagulation tests, were assayed for prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen level and platelet counts, using two different centrifugation speed for plasma preparation: centrifugation at 3580 rpm for 15 minutes and rapid centrifugation at 4000 rpm for five minutes. Paired sample t-test showed that there was a significant difference in the platelet count between the two groups (p=0.001). However, there was no significant difference in the normal APTT (p=0.16), abnormal APTT (p=0.80), abnormal PT (p=0.43) and the results of fibrinogen levels (p=0.36). In conclusion, rapid centrifugation at 4000 rpm for five minutes does not modify results of routine coagulation tests (PT, APTT and fibrinogen). It would be beneficial in providing rapid results for urgent coagulation tests.
Keywords : activated partial thromboplastin time, coagulation test, pre-analytical variable, prothrombin time, rapid centrifugation,
Abstrak
Pengemparan spesimen darah untuk menghasilkan plasma kurang platelet merupakan aspek penting bagi ujian koagulasi. Pengurangan masa yang diambil untuk mem-proses spesimen tanpa menjejaskan kualiti keputusan ujian yang dihasilkan adalah ideal bagi ujian rutin segera. Pengemparan untuk mendapatkan plasma kurang platelet selama 15 minit pada 3580 rpm secara rutin bagi ujian koagulasi akan menambahkan tempoh masa pengujian tersebut dan tempoh masa pengujian bagi ujian segera. Ka-jian ini dijalankan untuk mengetahui kesan pengurangan masa pengemparan ujian koagulasi bagi memenuhi tuntutan masa ujian segera (30 minit). Ujian prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen dan platelet dijalan-kan ke atas 79 sampel darah yang diterima untuk ujian koagulasi rutin, dengan meng-gunakan dua masa pengemparan berbeza untuk setiap sampel iaitu 15 minit pada 3580 rpm dan lima minit pada 4000 rpm. Ujian paired sample t-test menunjukkan ter-dapat perbezaan yang signifikan bagi pengiraan platelet di antara dua kumpulan ter-sebut (p=0.001). Walaubagaimanapun, tidak terdapat perbezaan signifikan bagi ujian APTT normal (p=0.16), APTT tidak normal (p=0.80), PT tidak normal (p=0.43) dan fi-brinogen (p=0.36) bagi kedua-dua kumpulan tersebut. Kesimpulannya, pengemparan yang dijalankan dalam masa yang singkat iaitu lima minit pada 4000 rpm tidak menje-jaskan keputusan ujian koagulasi rutin (PT, APTT dan fibrinogen). Justeru, keputusan kajian ini akan memberi manfaat dalam mengeluarkan keputusan segera, untuk ujian koagulasi khususnya.
Kata Kunci : activated partial thromboplastin time, pengemparan singkat, prothrombin time, ujian koagulasi, variasi pra-analisis,