Smear positivity in paediatric and adult tuberculosis: systematic review and meta-analysis.
Tuberculosis (TB) diagnosis continues to rely on sputum smear microscopy in many settings. We conducted a meta-analysis to estimate the percentage of children and adults with tuberculosis that are sputum smear positive.



We searched PubMed, MEDLINE, Embase, and Global Health databases for studies that included both children and adults with all forms of active TB. The pooled percentages of children and adults with smear positive TB were estimated using the inverse variance heterogeneity model. This review was registered in the PROSPERO database under registration number CRD42015015331.



We identified 20 studies meeting our inclusion criteria that reported smear positivity for a total of 18,316 children and 162,574 adults from 14 countries. The pooled percentage of paediatric TB cases that were sputum smear positive was 6.8 % (95 % Confidence Interval (CI) 2.2-12.2 %), compared with 52.0 % (95 % CI 40.0-64.0 %) among adult cases. Eight studies reported data separately for children aged 0-4 and 5-14. The percentage of children aged 0-4 that were smear positive was 0.5 % (95 % CI 0.0-1.9 %), compared with 14.0 % (95 % CI 8.9-19.4 %) among children aged 5-14.



Children, especially those aged 0-4, are much less likely to be sputum smear positive than adults. National TB programs relying on sputum smear for diagnosis are at risk of under-diagnosing and underestimating the burden of TB in children.
Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, USA.|Department of Epidemiology, Harvard School of Public Health, Boston, USA.
Amber
A
Kunkel
Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, USA.|Centre for Molecular Medicine Norway, Nordic EMBL Partnership, Oslo, Norway.|Department of Pharmacy, University of Tromso, Tromso, Norway.
Pia
P
Abel Zur Wiesch
Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, USA.
Ruvandhi R
RR
Nathavitharana
Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, USA.|Division of Global Health Equity, Brigham and Women's Hospital and Harvard Medical School, Boston, USA.
Florian M
FM
Marx
Division of Global Health Equity, Brigham and Women's Hospital and Harvard Medical School, Boston, USA.
Helen E
HE
Jenkins
Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, USA. theodore.cohen@yale.edu.
Ted
T
Cohen
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008853:Microscopy; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
Acid-fast bacilli; Age-specific; Child; Diagnosis; Sputum microscopy