The Indian journal of tuberculosis
November 4, 2025 · via Europe PMC
Truenat and Line Probe Assay in Pulmonary Tuberculosis: Understanding diagnostic discrepancies at low MTB loads.
Nishadh MJ, Mundodan JM, Babu A, Shaji LA.
AI summary — for doctors, generated from the abstract only
Among presumptive pulmonary TB cases with low or very low Truenat MTB results, only 61.8% were confirmed on line probe assay and many were culture negative, urging cautious interpretation.
What was studied
Study of 123 presumptive pulmonary TB cases in India with sputum Truenat low/very low MTB results, comparing with LPA and MGIT culture data from the NIKSHAY portal plus clinical and radiological details.
Key findings
- 61.8% confirmed positive on LPA; 45 cases culture negative
- Discordance higher in very low (45.7%) than low (33.0%) MTB group
- 11 culture-negative patients without clinical/radiological TB features were not treated and had no evidence of TB at up to one-year follow-up
Clinical relevance
This suggests low or very low Truenat results warrant confirmation with LPA or culture and clinical correlation before committing to treatment; the study is small and observational.
Who should care
Limitations
Small sample, retrospective data retrieval, and limited follow-up of untreated patients (n=11).
A low-level Truenat positive isn't always TB; confirm with culture or LPA and clinical findings.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.
Abstract
Background
Anecdotal evidence suggests that a few Tuberculosis patients with Nucleic Acid Amplification Tests (NAAT) result of Low/Very Low are later found to have MTB negative on culture. This study is to assess what proportion of presumptive Pulmonary Tuberculosis (PTB) cases with sputum Truenat showing low or very low MTB levels test positive on Line Probe Assays (LPA) and culture.
Methods
This study was conducted among presumptive PTB cases with Truenat showing low or very low MTB levels. Data including LPA and MGIT culture results were retrieved from the NIKSHAY portal, and additional clinical and radiological details were collected.
Results
Among 123 selected cases, 61.8 % were confirmed positive on LPA; 45 cases were culture negative. Discordance was higher in the very low MTB group (45.7 %) compared to the low MTB group (33.0 %). Eleven MGIT culture negative patients with no clinical or radiological features of PTB were not given ATT. None of them had clinical or radiological findings suggestive of PTB on follow-up up to one year.
Conclusions
The discordance of NAAT at low MTB loads with LPA and culture highlights the need for cautious interpretation. The findings underscore the importance of using LPA or MGIT culture for confirmation in suspected PTB cases.
DOI
10.1016/j.ijtb.2025.11.003
PMID
42457300
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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