Evaluation of Diagnostic Performance of Line Probe Assay on Smear-Negative Samples of Pulmonary Tuberculosis

• Published in: Curēus (Palo Alto, CA) Vol. 16; no. 4; p. e58298
• Main Authors: Nandwani, Sumi, Singhal, Sanjay, Gothi, Dipti, Singhal, Ritu, Perween, Naz, Gupta, Kavita, Bir, Raunak, Gunasekaran, Jayanthi, Soni, Anushka, Chaudhary, Urmila
• Format: Journal Article
• Language: English
• Published: United States Cureus Inc 15.04.2024; Cureus
• Subjects: Age groups; Antibiotics; Drug resistance; Infectious Disease; Medical diagnosis; Public Health; Pulmonology; Statistical analysis; Tuberculosis; Germany; pulmonary tuberculosis; acid-fast bacilli; first-line drug sensitivity testing; mycobacterium tuberculosis complex detection; rifampicin resistance; isoniazid resistance; line probe assay; diagnostic utility of lpa; ziehl-neelsen stain; smear-negative samples
• ISSN: 2168-8184; 2168-8184
• DOI: 10.7759/cureus.58298

This study aims to compare the performance of line probe assay (LPA) on smear-negative samples with that of smear-positive samples for diagnosing pulmonary tuberculosis (PTB) and first-line drug sensitivity testing (FL DST). A total of 196 sputum samples including both smear-positive (112) and negative (84) samples of patients suspected of PTB were subjected to LPA for TB detection and FL DST. TB culture followed by MPT 64 Ag was done and conventional FL DST was performed on all culture-positive isolates. Results of LPA on smear-negative were compared with smear-positive samples. The LPA confirmed the diagnosis of PTB in 104/112 smear-positive cases but in only 36/84 smear-negative cases. The assay had 47.36%, 72.72%, and 88.88% sensitivity and 86.96%, 95.23%, and 95.65% specificity in smear-negative cases compared to 89.09%, 95.83%, and 98.07% sensitivity and 100%, 98.36%, and 98.24% specificity in smear-positive cases for detecting (MTB), rifampicin (RMP) resistance, and isoniazid (INH) resistance, respectively. LPA performance was better on smear-positive than smear-negative sputum samples. Further larger studies are needed to justify the use of LPA on smear-negative pulmonary samples for diagnosis.