Routine diagnosis of intestinal microsporidiosis in clinical diagnostic laboratories relies mostly on
detection of microsporidial spores via special staining and microscopic techniques. This paper describes
the comparative evaluation of Calcofl uor White M2R method, with modifi ed Gram-chromotrope
Kinyoun method as the reference standard. One hundred and six stool samples were examined for the
presence of microsporidial spores. Sensitivity, specifi city, positive and negative predictive values of
the Calcofl uor White M2R method compared to the reference technique were 95.2%, 4.3%, 78.2%
and 20.0%, respectively. The positive predictive value (PPV) was 78.2% and the negative predictive
value (NPV) was 20.0%. Despite low specifi city of the CFW method due to its ability to stain
chitinous wall of microorganisms, the presence of distinct deep-blue horizontal or equitorial stripes in
microsporidial spores in modifi ed Gram-chromotrope Kinyoun would likely reduce the false positive
results obtained in the Calcofl uor White M2R. Hence, the simultaneous use of these two methods
would give better performance and accuracy for the detection of microsporidial spores in patients
with intestinal microsporidiosis.