Comparative cost and performance of light-emitting diode microscopy in HIV-tuberculosis-co-infected patients
European Respiratory Journal
Division of Medical Microbiology, UCT Lung Institute, South Africa; Lung Infection and Immunity Unit, Division of Pulmonology and Clinical Immunology, UCT Lung Institute, South Africa; Clinical Research Support Unit, Dept. of Medicine, South Africa; Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, South Africa; National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa; Dept. of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada; Dept. of Infection, University College London Medical School, London, United Kingdom
Light-emitting diode (LED) microscopy has recently been endorsed by the World Health Organization (WHO). However, it is unclear whether LED is as accurate and cost-effective as Ziehl-Neelsen (ZN) microscopy or mercury vapour fluorescence microscopy (MVFM) in tuberculosis (TB)-HIV-co-infected subjects. Direct and concentrated sputum smears from TB suspects were evaluated using combinations of LED microscopy, ZN microscopy and MVFM. Median reading time per slide was recorded and a cost analysis performed. Mycobacterial culture served as the reference standard. 647 sputum samples were obtained from 354 patients (88 (29.8%) were HIV-infected and 161 (26%) were culture-positive for Mycobacterium tuberculosis). Although overall sensitivity of LED compared with ZN microscopy or MVFM was similar, sensitivity of all three modalities was lower in HIV-infected patients. In the HIV-infected group, the sensitivity of LED microscopy was higher than ZN microscopy using samples that were not concentrated (46 versus 39%; p=0.25), and better than MVFM using concentrated samples (56 versus 44; p50.5). A similar trend was seen in the CD4 count <200 cells·mL -1 subgroup. Median (interquartile range) reading time was quicker with LED compared with ZN microscopy (1.8 (1.7-1.9) versus 2.5 (2.2-2.7) min; p≤0.001). Average cost per slide read was less for LED microscopy (US$1.63) compared with ZN microscopy (US$2.10). Among HIV-TB-co-infected patients, LED microscopy was cheaper and performed as well as ZN microscopy or MVFM independent of the staining (ZN or auramine O) or processing methods used.
adult; article; bacterium culture; CD4 lymphocyte count; controlled study; cost effectiveness analysis; diagnostic accuracy; diagnostic test accuracy study; female; human; Human immunodeficiency virus infection; intermethod comparison; LED microscopy; light emitting diode; major clinical study; male; mercury vapor fluorescence microscopy; microscopy; mixed infection; Mycobacterium tuberculosis; priority journal; sensitivity analysis; sensitivity and specificity; sputum smear; standard; tuberculosis; Ziehl Neelsen microscopy; Adult; AIDS-Related Opportunistic Infections; Coinfection; Cost-Benefit Analysis; Female; Humans; Male; Microscopy; Middle Aged; Mycobacterium tuberculosis; Sensitivity and Specificity; Sputum; Staining and Labeling; Tuberculosis, Pulmonary