The widal test is a test for diagnostic of thyfoid fever serology. Widal test aims to
detect the presence of antibodies against Salmonella antigen, by measuring the
degree of agglutination of antibody titer to antigen O and H in sample. In this
research Widal test was performed using serumand plasma samples. This study
aims to determine whether there is a difference in the value of titer on the Widal test
between serum samples and plasma EDTA samples. This type of research is an
experimental study. Samples were taken from patient suspected of thyfoid fever of
10 sample in the Laboratory of SM Raja Amplas in 2018. The result of comparative
titer Widal test using serum and plasma samples obtained results 30% of the 10
samples examined there are differences in the value of Widal titer but does not affect
the final diagnosis of typhoid fever. The value of the Widal test titer using plasma is
lower than the value of Widal Titer with the serum samples. The use of plasma
samples to determine the Widal titer is particularity susceptible to mingling with the
erythrocytes due to the presence of anticoagulant particles but does not affect the
result of the Widal test. EDTA anticoagulants do not damage the antibodies
contained in the serum, this can be seen in the results of the study, there were no
differences in each sample examined, so the difference in results obtained due to
other factors, namely the error of researchers in the Widal test. The Widal test using
serum samples can gives results according to the actual circumstances because
serum is not contaminated by EDTA anticoagulants.