USING SPUTUM AND TONGUE SWAB SPECIMENS FOR IN-HOME POINT-OF-CARE TARGETED UNIVERSAL TESTING FOR TB OF HOUSEHOLD CONTACTS: AN ACCEPTABILITY AND FEASIBILITY ANALYSIS

  1. Charl Bezuidenhout
  2. Lawrence Long
  3. Brooke Nichols
  4. Gesine Meyer-Rath
  5. Matthew P Fox
  6. Sharon Olifant
  7. Grant Theron
  8. Kuhle Fiphaza
  9. Morten Ruhwald
  10. Adam Penn-Nicholson
  11. Bernard Fourie
  12. Andrew Medina-Marino
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Abstract

Introduction

Effective strategies are needed to facilitate early detection and diagnosis of tuberculosis (TB). The over-reliance on passive case detection, symptom screening, and collection of sputum, results in delayed or undiagnosed TB, which directly contributes to on-going TB transmission. We assessed the acceptability and feasibility of in-home, Targeted Universal TB Testing (TUTT) of household contacts using GeneXpert MTB/RIF Ultra at point-of-care (POC) during household contact investigations (HCIs) and compared the feasibility of using sputum vs. tongue swab specimens.

Methods

Household contacts (HHCs) receiving in-home POC TUTT as part of the TB Home Study were asked to complete a post-test acceptability survey. The survey explored HHC’s level of comfort, confidence in the test results, and the perceived appropriateness of in-home POC TUTT. We used the Metrics to Assess the Feasibility of Rapid Point-of-Care Technologies framework to assess the feasibility of using sputum and tongue swab specimens for in-home POC TUTT. Descriptive statistics were used to report participant responses and feasibility metrics.

Results

Of 313 eligible HHCs, 267/313 (85.3%) consented to in-home POC TUTT. Of those, 267/267 (100%) provided a tongue swab and 46/267 (17.2%) could expectorate sputum. All specimens were successfully prepared for immediate, in-home testing with Xpert Ultra on GeneXpert Edge. Of 164 tongue swab tests conducted, 160/164 (97.6%) generated a valid test result compared to 44/46 (95.7%) sputum-based tests. An immediate test result was available for 262/267 (98.1%) individuals based on in-home swab testing, and 44/46 (95.7%) based on in-home sputum testing. The mean in-home POC TUTT acceptability score (5=highly acceptable) was 4.5/5 (SD= 0.2).

Conclusion

In-home, POC TUTT using either sputum or tongue swab specimens was highly acceptable and feasible. Tongue swab specimens greatly increase the proportion of HHCs tested compared to sputum. In-home POC TUTT using a combination of sputum and tongue swabs can mitigate shortcomings to case detection.

KEY MESSAGE

What is already known on this topic

  • TB transmission among household contacts of people with TB is a public health concern.

  • The delivery of community-based diagnostic testing for TB is challenging and the reliance on sputum continue to hamper universal testing and result in diagnostic delay.

What this study adds

  • This is the first study to assess the acceptability of universal in-home point-of-care TB testing of household contacts during household contact investigations.

  • This study assesses the feasibility of different specimen types for immediate in-home point-of-care TB testing including tongue swabs and sputum.

How this study might affect research, practice or policy

  • Household contacts perceived in-home targeted universal TB testing to be highly acceptable, prompting the need for further investigation into the cost-effectiveness of such strategies to improve early case detection.

  • The use of tongue swabs as an additional or alternative sample type to sputum could increase testing and improve early case detection.

Article activity feed

  1. Version published to 10.1101/2024.11.01.24316570v1 on medRxiv