Comparison of the Formalin- Ether and the Katz Kato in The Parasitological Diagnosis of Human Fascioliasis

ABSTRACT Human fascioliasis is an endemic disease in the Guillan province and it has became a public health problem in the port of Anzali. Thousands of people in this area were infected during the two outbreaks in 1987 and 1998. If the mature worm settles in the liver, finding the ova in the stool is the most reliable diagnosis of the infection. Therefore selecting the most sensitive parasitological method is of value in prompt diagnosis and treatment of the disease. The Formalin-Ether method which is a routine procedure in the clinical laboratories is compared to Katz-Kato which is usually used for quantitative parasitological assessments, but is also reported as being useful in the diagnosis of human fascioliasis. Stool samples of 184 suspected patients , refered to the parasitology lab of the Guillan university of medical sciences, were consecutively collected . Patients had liver-free diets at least 3 days prior to specimen collection. Each sample was examined by both the formalin-ether and the Katz-Kato methods, performed separately by two technologists neither of whom knew the results of the other one(blinding). In order to see the outcomes of the tests on the repeated samples, 3 stool samples were collected at 2 - 3 days intervals from 69 patients and examined as before. For the first part, 44 samples were positive and 124 were negative with both methods. 9 samples were only positive with the formalin-ether and 7 samples were exclusively positive with the Katz-Kato. For the second part (3 samples for each patient) 22 patients were diagnosed as positive and 46 patients as negative with both methods. Only one patient was exclusively positive with Katz-Kato. Comparing the results of 184 samples with Kappa statistics an agreement of 0.78 (very good) was found. This agreement increased to 0.98 (excellent) for repeated samples of 69 patients.