Clinical Report: Evaluating the Effectiveness of the Active Melioidosis Detect Plus Rapid Test

Overview

This prospective study evaluates the diagnostic accuracy of the Active Melioidosis Detect Plus rapid diagnostic test (AMD-RDT) for detecting Burkholderia pseudomallei in throat swabs. Testing at laboratories in Cambodia and Laos shows low sensitivity despite high specificity, with findings that do not support routine use on throat swabs.

Background

Melioidosis, caused by B. pseudomallei, is a major cause of morbidity in tropical and subtropical regions. Culture remains the diagnostic gold standard but typically requires at least 48 hours and specialized resources often unavailable in high-burden settings. Throat swabs are frequently collected from children and adults unable to expectorate and may provide the only culture-positive specimen.

Objective

To evaluate AMD-RDT accuracy on throat swabs, using B. pseudomallei culture as the reference standard.

Approach

Researchers conducted a prospective diagnostic accuracy study using a 1:2 case-control design. Each culture-positive throat swab served as a case, with the next two consecutive culture-negative swabs selected as controls. Stored aliquots underwent AMD-RDT testing, with results read after 15–20 minutes. Readers were not blinded to culture results.

Data Highlights

• B. pseudomallei was cultured from 38 of 1451 throat swab specimens (2.6%).

• Researchers tested 38 culture-positive specimens and 76 culture-negative controls.

• AMD-RDT sensitivity was 18.4% (95% CI, 9.2%–33.4%).

• Specificity was 100% (95% CI, 95.2%–100%).

Key Findings

• AMD-RDT positivity occurred only in specimens positive on direct culture.

• All 5 specimens with growth abundance of at least 2+ were AMD-RDT positive, compared with 2 of 33 specimens with less growth.

• Positive AMD-RDT results occurred only when culture detected B. pseudomallei within 48 hours.

• The throat swab was the sole culture-positive specimen in 20 of 38 cases (52.6%).

• Nine of 38 culture-positive specimens (23.7%) required enrichment culture for detection.

Interpretation

Low antigen burden likely contributes to poor AMD-RDT sensitivity on throat swabs. Despite high specificity, a negative result cannot reliably exclude melioidosis.

Limitations

Delayed testing may have allowed degradation of the capsular polysaccharide targeted by the test, although accuracy was similar for testing within and after 4 days of specimen receipt. Using one swab for both culture and AMD-RDT testing may have limited yield. Recruitment ended before the planned sample size of 234 specimens was reached.

Clinical Implications

The authors do not recommend routine AMD-RDT use on throat swabs. Throat swabs and enrichment culture remain essential components of the diagnostic workup for melioidosis.

Conclusion

The AMD-RDT lacks sufficient sensitivity for routine testing of throat swabs. These findings reinforce the diagnostic value of throat swab culture, including enrichment.

Related Resources & Content

1. Diagnostic accuracy of the Active Melioidosis Detect Plus rapid test for detection of Burkholderia pseudomallei in throat swabs — Arjun Chandna, Sena Sao, Joy Silisouk, et al. — International Journal of Infectious Diseases, volume 172, article 109114, 2026; accepted September 9, 2026.