Cost-effectiveness of polymerase chain reaction versus Ziehl-Neelsen smear microscopy for diagnosis of tuberculosis in Kenya.

BACKGROUND: Laboratory services, particularly in large sub-Saharan cities, are overstretched, and it is becoming difficult both for patients and health staff to adhere to the diagnostic procedures for tuberculosis. Alternative techniques would be welcome. The polymerase chain reaction (PCR) has the potential to be cost-effective. We compared the cost-effectiveness of two diagnostic strategies, Ziehl-Neelsen (ZN) on three specimens followed by chest X-ray (CXR), and AMPLICOR MTB PCR on the first specimen only.
METHODS: Three sputum samples were collected from tuberculosis (TB) suspects attending the Rhodes Chest Clinic, Nairobi. All samples were subjected to ZN, PCR and Löwenstein-Jensen culture used as gold standard. CXR was used to diagnose smear-negative TB. Cost analysis included health service and patient costs.
RESULTS: Costs per correctly diagnosed case were US dollar 41 and dollar 67 for ZN and PCR, respectively. When treatment costs were included, including treatment of culture-negative cases, PCR was more cost-effective: dollar 382 vs. dollar 412.
CONCLUSION: PCR may be an alternative in settings with many patients. PCR is patient friendly, CXR is not necessary and, unlike ZN, its performance is hardly affected by the human immunodeficiency virus. PCR can handle large numbers of specimens, with results becoming available on the same day.