Evaluation of a New Primer In Comparison With Microscopy for the Detection of Giardia lamblia Infection in Stool Samples

Background: Among the most important parasitic disease, causing diarrhea, Gi­ardia lamblia is noteworthy. Nowadays detection methods for these parasites in­clude parasitological methods such as microscopic examination. The sensitivity of these methods relies on the expertise and experience of examiners. In contrast, molecular methods such as PCR are less dependent on the expertise of the exam­iner. Here we developed a PCR for the detection of G. lamblia genome in stool samples in comparison with microscopy, which is the gold standard. Methods:  For the evaluation of primers, 22 positive samples and 47 negative samples were used. QIAamp DNA Stool Mini Kit (QIAGEN, Germany) was used for DNA extraction from feces. Primers for PCR were designed using Primer-BLAST which uses Primer 3 to designing specific primers ( NCBI / Primer-BLAST). Results: Sensitivity of the PCR was done with 100% (95%CI: 84.56-100) for the detection of G. lamblia DNA isolated from patients stool samples which were posi­tive for G. lamblia cysts and/or trophozoites using microscopy as gold standard. In comparison with microscopy, PCR had showed the specificity of 97.87% (95%CI: 88.71-99.95). Conclusion: We designed new primers for the Giardia, and PCR method for the rapid and accurate identification of Giardia parasites established. With considera­tion to the routine diagnosis techniques in medical parasitology and their limita­tions such as time consuming, laborious, less sensitivity etc. This G. lamblia PCR is a sensitive and specific application for the diagnosis of G. lamblia and provides us a reliable method in the routine intestinal parasitic infection laboratory diagnosis.