Piloting of locally developed dried tube specimen panels for Xpert®MTB/RIF assay proficiency testing in Nairobi, Kenya

  • M.W. Nganga
  • A.M. Musyoki
  • N.C. Menza
  • S. Bundi
  • J. Kiarie
  • M. Mbugua


Background: Continuous proficiency testing (PT) is a key component of external quality assurance component in Xpert MTB/RIF assay for tuberculosis. In Kenya, this exercise is poorly covered and frequently interrupted due to the limited supply of PT materials, which mainly come as donations from CDC-Atlanta, USA, but are insufficient for all the Xpert MTB/RIF sites, posing a risk of obtaining unreliable results that can negatively impact patients’ management and TB control programs.
Objective: This study aimed to develop in-country dried tube specimens (DTS) for Xpert MTB/RIF proficiency testing in Kenya and pilot them in all Xpert MTB/RIF- TB testing sites in Nairobi County.
Methods: A laboratory-based experimental design was adopted. DTS panels were developed following standard bacteriological procedures, and their accuracy and precision were assessed. We evaluated the performance of the developed DTS in all the 20 Xpert MTB/RIF- TB testing sites in Nairobi County from November to December 2019.
Results: Validation of developed DTS showed 100% concordance with the pretesting results. Ninety per cent (18/20) of piloted sites had satisfactory scores, 80% (16/20) excellent, 10% (2/20) unsatisfactory results. Ninety-six per cent of the laboratories results were concordant with the expected, whereas 4% (4/100) were discordant. Two Sites (2/20, 10%) recorded an error (code 5007).
Conclusion: Developed DTS panels showed a high-performance level as an Xpert/MTB/RIF quality assurance checker. There is a need to upscale production to satisfy quality assessment needs in all Xpert MTB/RIF testing sites in the Country by establishing a fully independent and sustainable local DTS production pipeline.


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eISSN: 0012-835X