A comparison study of different methods used in the detection of Giardia lamblia

The purpose of this study was to compare results obtained using a single fecal specimen for O&P examination, direct immunofluorescent assay (DFA), and three immunodiagnostic techniques.

Sixty-eight human fecal specimens were collected and examined by each method. The O&P and the DFA were used as the reference method.

The study was performed at the research laboratory in the Medical Technology Department at The University of Southern Mississippi.

The fecal specimens were collected from individuals with a suspected Giardia lamblia infection.

None.

The amount of agreement and disagreement between methods. 1. The sensitivity and specificity of each method. 2. The working time and cost per specimen for each method.

There was complete agreement among methods on 52 specimens (21 positive, 31 negative). Eight specimens were positive by all immunologic methods, but negative by O&P. The remaining eight specimens (12%) demonstrated discrepancies among methods. Sensitivity and specificity of each assay ranged from 91% to 100% and 89% to 100%, respectively. The cost per specimen ranged from $11.62 for the DFA method to $32.54 for the O&P method. The average cost per specimen for ELISA and EIA averaged $26.86.

The study supported findings of other investigators who concluded that immunologic methods have the greater sensitivity. The immunologic methods were more efficient, quicker, and economical than the conventional O&P method.