Pooling sputum testing to diagnose tuberculosis using xpert MTB/RIF and xpert ultra: a cost-effectiveness analysis

Area of Science:

• Medical Diagnostics
• Public Health
• Infectious Disease Management

Background:

• The World Health Organization (WHO) recommends molecular diagnostic tests like Xpert MTB/RIF (MTB/RIF) and Xpert Ultra (Ultra) for tuberculosis (TB) diagnosis.
• These recommended tests are costly and resource-intensive, necessitating cost-effective alternatives for wider implementation.

Purpose of the Study:

• To evaluate the cost-effectiveness of pooling sputum samples for TB diagnosis using MTB/RIF or Ultra cartridges.
• To determine if pooled testing offers a viable, resource-efficient alternative to individual testing.

Main Methods:

• A cost-minimization analysis was performed from a healthcare system perspective.
• Evaluated the cost-effectiveness of pooled versus individual sputum sample testing using MTB/RIF or Ultra cartridges.
• The primary indicator for cost-effectiveness was the number of individuals with TB detected.

Main Results:

• Pooled testing demonstrated comparable performance to individual testing (sensitivity 93.9% vs. 97.6%, specificity 98% vs. 97%).
• Mean unit cost per person tested decreased by 35.6% ($34.10 to $21.95 international dollars) with pooled testing.
• Mean unit cost per confirmed TB case decreased by 34.9% ($249.64 to $162.44 international dollars) with pooled testing.
• Savings are dependent on TB prevalence; pooled testing is not cost-effective if prevalence is ≥30%.

Conclusions:

• Pooled sputum testing is a cost-effective strategy for TB diagnosis, yielding substantial resource savings.
• This approach can expand testing capacity and affordability, especially in resource-limited settings.
• Pooled testing supports the WHO's End TB strategy by enabling increased diagnostic coverage.