Fifth year medical cadet, Phramongkutklao College of Medicine, 315 Ratchawithi
Road, Ratchathewi, Bangkok 10400, Thailand
Background : Currently, the detection of
human infection with B. hominis is usually based on simple smear and trichrome
staining examination under a light microscope of faecal samples. Recently it has
been shown that in vitro cultivation is a sensitive method to identify B.
hominis. However, there is no comparison of these 2 methods in terms of
sensitivity and specificity. Purpose : To
compare trichrome staining and in vitro cultivation for the detection of B.
hominis. Design : Diagnostic Study
Materials and Methods : Study in 337 conscripts
of 2nd Infantry Regiment, Queens Guard, Prachinburi province who consented to
participate this research during 16th20th February 2003. Each collected fresh
stool specimens were checked for the parasite using three methods including
simple smear, trichrome staining and cultivation in Jones medium.
Results : 102 of the samples were found to be
B. hominis positive by in vitro cultivation. The sensitivity and specitivity of
trichrome staining are 40.2% and 80.4% compared to that of in vitro cultivation.
Conclusion : From the study, we found that the sensitivity of
trichrome staining was rather low but the specificity was high. Thus, culture
would be particularly beneficial when the subject is excreting small numbers of
B. hominis and/or when a microscopist checking stained specimen is uncertain if
it is positive or negative for B. hominis.
Key Word : Blastocystis hominis, Trichrome
staining, In vitro cultivation