Effects of Storage Time and Temperature on The samples of Routine Coagulation Tests

Abstract

The main objective of this study To determine the effects of storage temperature and time for prothrombin time and activated partial thromboplastin time at various intervals at both room temperature and refrigerator. This was case study conducted in Turkish Teaching Hospital in Khartoum State during the period from March to April 2017. After obtaining the consent a total of so samples were collected. The blood specimens were processed and analyzed for prothrombin time and activated partial thromboplastin time. Coagulation tests (Prothrombin time and activated Partial thromboplastin time) were performed immediately specified times after phlebotomy up to 24 hours (0, 2, 4 and 24 hours) both at room temperature (RT) and refrigerator. Our data show the means results of Prothrombin time(PT) immediately after phlebotomy at 0 hour was (12.5020 seconds) and after 2 hour storage (12.3800 seconds), and after 4 hour (12.3260 seconds) and after 24 hour (14.6100 seconds) at room temperature (RT), and when samples storage at 4℃ the result after 2 hour (12.4940 seconds), 4 hour (12.4920 seconds) and after 24 hour (11.3480 seconds). The Means results of activated Partial thromboplastin time (APTT) immediately after phlebotomy at 0 hour (hr) was (35.4900 seconds) and after 2 hour storage (36.2640 seconds), and after 4 hour (37.0400 seconds) and after 24 hour (42.0420 seconds) at room temperature (RT), and when samples storage at 4℃ the result after 2 hour (36.4240 seconds), 4 hour (37.0320 seconds) and after 24 hour (42.2240 seconds). The PT measurements at 0 hr showed non-significant differences when compared with measurements at 2hr with P-vale (0.614) and 4 hr with P-value (0.467) at RT, also showed non-significant differences when compared with measurements at 2hr with P-vale (0.978) and 4 hr with P-value (0.973) at 4℃, while the differences were significant with measurements at 24 hr at RT and refrigerator with P-value (0.000) for both. There was an increase in the PT results over time when samples were stored at RT and at 24 hr. On the other hand, when samples were stored in the refrigerator, the PT results obtained decreased over time at 24 hours. For APTT, comparisons between measurements at 0 hr showed non-significant differences when compared with measurements at 2hr with P-vale (0.431) and 4 hr with P-value (0.364) at RT, also showed non-significant differences when compared with measurements at 2hr with P-vale (0.345) and 4 hr with P-value (0.120) at 4℃, while the differences were significant with measurements at 24 hr at RT and refrigerator with P-value (0.000) for both. The levels of APTT measurements were increased over storage time for samples kept at RT and refrigerator. This study concluded that a prolonged storage time more than 4 hours could induce statistically significant changes for some routine coagulation test results (both at RT and at refrigerator), but that these changes remained within the desirable limits of variation, and had no clinical relevance.