Paediatric Tuberculosis Diagnosis Using Mycobacterium Tuberculosis Real-time Polymerase Chain Reaction Assay: a Systematic Review and Meta-analysis
Authors: Babafemi Emmanuel Oladipo , Cherian Benny P , Ouma Beatrice , Mogoko Gilbert Mangua 
Published: January 2021

Abstract
Background:Rapid and accurate diagnosis of paediatric tuberculosis (TB) is key to manage the disease and to control and prevent its transmission. Collection of quality sputum samples without invasion methods from paediatrics (age <16 years) with presumptive pulmonary tuberculosis (PTB) remains a challenge. Clinical management is especially challenging, and recommendations are based on restricted evidence. Many established diagnostic methods suffer from low sensitivity or delay of timely results and are inadequate for rapid detection of Mycobacterium tuberculosis (MTB) in pulmonary and extra-pulmonary clinical samples. This study assessed the overall accuracy of a real-time polymerase chain reaction (RT-PCR) based assay, with a turn-a-round time of 2 h, for routine diagnosis of MTB in different samples from paediatrics with active pulmonary and extra-pulmonary tuberculosis using mycobacterial culture as the gold standard in clinical microbiology laboratories.Methods:We conducted a systematic review and meta-analysis to examine the diagnostic accuracy of RT-PCR based assay for the detection of MTB in paediatric clinical samples. A systematic literature search was performed for publications in any language. The following sources were used MEDLINE via PubMed, EMBASE, BIOSIS Citation Index, Web of Science, SCOPUS, ISI Web of Knowledge, World Health Organization and Centres for Disease Control and Prevention websites, Cochrane Infectious Diseases Group Specialised Register, and grey literature. Twenty studies (5,536 specimens) that met set inclusion criteria were included. Bivariate random-effects model of meta-analysis were performed to generate pooled summary estimates (95% CIs) for overall accuracy of RT-PCR based assay compared to mycobacterial culture as the reference standard. Results:Of the 1592 candidate studies, twenty eligible studies met our inclusion criteria. In total, the review and meta-analysis included 5, 536 (3, 209 PTB and 2, 327 EPTB). Summary estimates for pulmonary TB (11 studies) were as follows: sensitivity 56 (95% CI 51-62), specificity 97 (95% CI 96-98), positive likelihood ratio 70.73 (95% CI 8.55-585.40), negative likelihood ratio 0.43 (0.28-0.66), diagnostic odds ratio 193.06 (95% CI 51.21- 727.83) and summary receiver operating characteristic (SROC) area under curve 0.98. Summary estimates for extra-pulmonary TB (10 studies) were as follows: sensitivity 87 (95% CI 82-91)) specificity 100 (95% CI 99-100), positive likelihood ratio 111.91(53.97-232.04), negative likelihood ratio 0.15 (0.07-0.30), diagnostic odds ratio 1337.84 (95% CI 441.92- 4050.12) and summary receiver operating characteristic (SROC) area under curve 0.99. There was significant heterogeneity in sensitivity and specificity among the enrolled studies (p< 0.001).Conclusions:Our results suggested that the RT-PCR based assay could be a useful test for the diagnosis of paediatrics TB with high sensitivity and specificity in low-income/high-burden and upper medium income/low-burden settings.RT-PCR assay demonstrated a high degree of sensitivity for extra-pulmonary TB and good sensitivity for pulmonary TB. It indicated a high degree of specificity for ruling in TB infection from sampling regimes. This was acceptable but may better as a rule out add-on diagnostic test. RT-PCR based assays demonstrate both a high degree of sensitivity in extra-pulmonary and moderate sensitivity in pulmonary samples and rapidity of detection of TB which is an important factor in achieving effective global control and for patient management in terms of initiating early and appropriate anti-tubercular therapy. Systematic review registration: PROSPERO CRD42018104052