The Effect of Time and Temperature Variables on Some Routine Coagulation Tests among Subjects of African Descent in Sokoto, North Western Nigeria

Abstract

This study evaluated the effects of time and temperature variables on routine Prothrombin Time test and Activated Partial Thromboplastin Time (APTT) test among subjects of African descent in Sokoto, North Western Nigeria. Samples of 99 subjects made up of 49 male and 50 female subjects with mean age 38.3 ± 22.3 years. Coagulation tests were performed immediately specified times after phlebotomy up to 24 hours (0, 1, 2, 3, 4 and 24 hours at room temperature of 40 degrees C. Our data demonstrate that prothrombin time and APTT results are stable for up to 2 hours, remaining constant regardless of storage conditions. Post hoc tests using Bonferroni correction revealed that there were increases in PT time from 0 hour to 4 hours (17.82 ± 0.61 seconds vs 18.30 ± 0.59 seconds, respectively), from 0 hour to 24 hours (17.82 ± 0.61 seconds vs 18.48 ± 0.59 seconds, respectively), from 2 hours to 4 hours (17.89 ± 0.58 seconds vs 18.30 ± 0.59 seconds), from 2 hours to 24 hours (17.89 ± 0.58 seconds vs 18.48 ± 0.58 seconds), which were all statistically significant (p = 0.002 and p < 0.000, p < 0.000, p < 0.000, respectively). However, the increase in PT time from 0 hour to 2 hours (17.82 ± 0.61 seconds vs 17.89 ± 0.59 seconds, respectively) and from 4 hours to 24 hours (18.30 ± 0.59 vs 18.48 ± 0.59 seconds, respectively) were not statistically significant (p = 1, p = 0.428). A repeated measure ANOVA determined that mean PTTK time differed statistically significantly between time points F (3, 291) = 119.22, p < 0.001. Post hoc tests using Bonferroni correction revealed that there were increase in PTTK time from 0 hour to 2 hours (37.86 ± 1.04 seconds vs 39.94 ± 1.07 seconds, respectively), from 0 hour to 4 hours (37.86 ± 1.04 seconds 80vs 42.34 ± 1.11 seconds, respectively), from 0 hours to 24 hours (37.86 ± 1.04 seconds vs 44.93 ± 1.20 seconds), from 2 hours to 4 hours (39.94 ± 1.07 seconds vs 42.34 ± 1.11 seconds), from 2 hours to 24 hours (39.94 ± 1.07 seconds vs 44.93 ± 1.20 seconds) and from 4 hours to 24 hours (42.43 ± 1.11 vs 44.93 ± 1.20 seconds), which were all statistically significant at p < 0.001). Therefore, we conclude that there are no statistically significant differences in the PT and APTT between 0 and 2 hours. A longer timing (after 2 hours) from phlebotomy collection of blood from respondents elicited a statistically significant increase in the PT and APTT result. There were no statistically significant differences in the PT and APTT result determined 4 hours and 24 hours after phlebotomy. Longer timing from collection of blood from respondents elicited a statistically significant increment/increase in the clotting time using PTTK. Our data demonstrate that PT and APTT results are stable for 2 hours remaining constant regardless of storage conditions.

Effect of storage time on prothrombin time and activated partial thromboplastin time: study at a tertiary care center in Kashmir valley

“…6 In a similar study by Ikhuenbor et al prothrombin time (PT) & activated partial thromboplastin time (APTT) results were stable for upto 2 hours and remaining constant regardless of storage conditions. 7 Kemkes-Matthes et al In his study concluded that the acceptable storage time can be extended to 24 h for PT. 8 Adcock et al in his study demonstrated that PT results are stable for upto 24 h, remaining constant regardless of storage conditions.…”

Assessment of Stability of Prothrombin Time, International Normalized Ratio, and Activated Partial Thromboplastin Time Under Different Storage Conditions in Human Plasma

“…[11,12]. Ikhuenbor et al concluded that a longer timing (after two hours) from phlebotomy showed a statistically significant increase in the PT and APTT results [3].…”

“…Prothrombin time (PT) and activated partial thromboplastin time (APTT) are commonly used coagulation tests to assess pathological changes in hemostasis and coagulation systems [1,2]. In addition, the international normalized ratio (INR) is used to monitor oral anticoagulant therapy for reducing the risk of thromboembolic events and minimizing the incidence of bleeding complications [3]. The laboratory testing process is partitioned into three phases, namely, pre-analytical, analytical, and post-analytical phases.…”

“…Several studies have shown that PT, INR, and APTT determinations may be stable for periods more than the currently recommended guidelines [4,5]. A range of storage times for PT, INR, and APTT from four hours to 24 hours and temperatures ranging from 4°C to 40°C have been studied [1,3]. Furthermore, it has been suggested that each laboratory should establish its acceptable storage times [2].…”