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Background: Cryptosporidium is a cause of diarrheal disease worldwide, which generally affecting children and the immunosuppressed patients. Conventional diagnostic method is direct smear preparation, modified Zeil-Nelson staining and screening for Cryptosporidium oocyst. The aim of this study was to compare sensitivity and specificity between modified Zeil-Nelson staining and direct fluorescent antibody assay.
Materials and Methods: We prepared direct smears from 2500 fecal samples. The smears were stained by modified Zeil-Nelson technique. Then the positive and randomized negative cases were studied using direct fluorescent antibody assay.
Results: By modified Zeil-Nelson staining method, 30 cases were positive for cryptosporidium oocyst and direct fluorescent antibody assay confirmed 27 of 30 positive cases. Direct fluorescent antibody assay could not detect any positive case from 114 randomized negative samples by modified Zeil-Nelson staining method which selected according statistical calculation. Therefore their sensitivity, specificity, positive predict value and negative predict value were 90%, 100%, 100% and 97/5% respectively.
Conclusion: Our results presented that the sensitivity of immunofluorescent technique was less than modified Zeil-Nelson staining method, but specificity of both methods were 100%. So, modified Zeil-Nelson staining method is a good technique for Cryptosporidium detection in med and research Labs.