Comparison of Microscopy and PCR for Detection of and in Human Stool Specimens in a Resource Limited Setting in Western Kenya.

Background: Accurate diagnosis of Giardia lamblia and Entamoeba histolytica is important since these intestinal parasites account for a significant proportion of morbidity and mortality globally. Microscopy is the key diagnostic test used for diagnosis of the two parasites. Other tests including rapid diagnostic tests and polymerase chain reaction have been developed to improve the detection of these parasites. Most of these newer tests are not affordable in resource limited settings, hence the over reliance on microscopy. The objective of this study was to determine the reliability of microscopy in a resource limited setting in Western Kenya, a region endemic for the two intestinal parasites.

Methods: Polymerase chain reaction, the gold standard test, was performed on stool samples suspected for G. lamblia and E. histolytica. Microscopy was then performed on the same samples and the two tests compared.

Results: Microscopy was found to be 64.4% sensitive, 86.6% specific for the detection of G. lamblia. Additionally, this test was 64.2% sensitive and 83.6% specific for the diagnosis of E. histolytica. Cohen's kappa values of 0.51 and 0.47 were determined for microscopy for G. lamblia and E. histolytica respectively. McNemar's test revealed a significant difference between the two tests, P<0.001.

Conclusion: This study found microscopy to be a reliable diagnostic test in this resource limited setting.