Symptom-based screening tool in ruling out active tuberculosis among HIV-infected patients eligible for isoniazid...

We assessed the usefulness of the National TB and Leprosy Control Program (NTLP) symptom-based tuberculosis (TB) screening tool in identifying HIV-infected patients eligible for isoniazid preventive therapy in Muhimbili National Hospital, Dar es Salaam Tanzania.

Descriptive cross-sectional study. Data collected included socio-demographic and clinical data. Chest X-ray, sputum for acid-fast bacilli (AFB) microscopy, mycobacterial culture, CD4 + count and complete blood count were performed. Patients were considered not having active TB if they presented with no symptom in the screening tool, which comprised these symptoms: cough, fever and excessive night sweats for ≥2 weeks; weight loss of ≥3 kg in 4 weeks and haemoptysis of any duration. The reference standard was a negative culture for Mycobacterium tuberculosis.

We enroled 373 patients, of whom 72.1% were females. Active pulmonary TB was found in 4.1% (14/338) of the participants as defined by a positive culture. The sensitivity and specificity of the NTLP screening tool were 71.4% (10/14) and 75.9% (246/324), respectively. False-negative rate was 28.6% (4/10). Cough, fever for ≥2 weeks and weight loss were independent predictors of NTLP-defined TB. Cough ≥2 weeks predicted TB when a positive culture was used to define TB.

The screening tool had fairly good sensitivity and specificity for TB screening; however, there is a possibility that about 29% of the screened population will be given IPT while they are supposed to receive a full course of TB treatment.