| dc.description.abstract | Citrated blood specimens received in some
laboratories for coagulation testing such as
prothrombin time (PT), Activated Partial
Thromboplastin Time (APTT), and Thrombin
Time (TT) are stored for long periods due to
many reasons. The objective of this randomized
complete block design study was to describe the
effect of storage time of uncentrifuged citrated
blood specimens on results of testing. Blood
samples were collected from 40 selected patients
coming to General Hospital, Kalutara. PT, APTT
and TT tests were performed after phlebotomy at
specified times up to 8hours (0-2 hours baseline,
4 hour and 8 hours at room temperature) using
coagulation analyzer. The results were evaluated
using paired t-test and P ≤ 0.05 was considered to
be statistically significant. Mean PT, APTT and TT
values of samples stored for 4 hours and 8 hours
before centrifugation were compared with the
mean values obtained at 0-2 hours. When samples
were stored for 0-2 hours, 4 hours and 8 hours the
mean(SD) PT were 20.96 (8.17), 21.85 (8.96) and
24.06 (10.17) respectively and the mean(SD) APTT
were 42.77 (13.69), 48.27(16.29) and 54.03 (18.12)
respectively while mean(SD) TT values were 16.16
(4.31), 18.04 (3.82)and 18.78 (4.04) respectively.
When samples were stored for 4 hours and 8 hours
at room temperature, significant differences were
found in mean PT (p=0.001), APTT (p=0.001) and
TT (p=0.001) compared to mean of samples stored
for 0-2 hours. Storage of blood after collection for
a longer period elicited a statistically significant
increase in the normal PT, APTT and TT results
and abnormal PT, APTT and TT results. Therefore,
above tests should be determined within 2 hours
of blood collection. | en_US |
