The validity of the Questionnaire to identify Schistosoma haematobium infection

Background: Schistosomiasis is considered the most important water-based disease, Estimation of S.haematobium infection has been recognized in Egypt since ancient times, hematuria known as AAA disease. One of the symptoms of urinary schistosomiasis is visible blood in urine, since this is normally well recognized by children, the assessment of urinary schistosomiasis can be undertaken rapidly and accurately by using a simple questionnaire. This study was done to test the validity of self-reported blood in urine by questionnaire compared to parasitological methods. Subjects and methods: Across -sectional study was carried. To overall total sample was 1000 patients of different ages, data about the history of recent symptoms of schistosomiasis as haematuria and dysuria were collected. Also, urine microscopic examination was done for the detection of S.haematobium eggs by sedimentation centrifugation and nuclepore filtration techniques. Results: The results showed that haematuria by questionnaire had a sensitivity of 54.4% and specificity of 90.8%. When dysuria was considered, sensitivity increased to 75.95% but specificity decreased to 51.2%. When both self-reported haematuria and dysuria were considered, sensitivity was 68.3% and specificity 85%, in between the previous results. PPVs ranged between 11.8% and 33.6% whereas NPVs ranged between 95.9% and 96.1%. As for diagnostic efficiency, it was best for haematuria (87.9%).
Conclusion: questionnaire has a moderate sensitivity, a simple questionnaire asking "Did you have blood in urine during the last month?" and "Did you suffer from schistosomiasis during the last months?" is a validated tool that allows for a decision to be taken, a questionnaire was shown to have a very high negative predictive value 96%, so that it is safe to use it to identify communities with a low prevalence so that they can be excluded from the first phases of a control program, but microscopic examination is better and not expensive for diagnosis of urinary schistosomiasis infection.