Comparative cost and performance of light-emitting diode microscopy in HIV-tuberculosis-co-infected patients

A. Whitelaw, J. Peter, H. Sohn, D. Viljoen, G. Theron, M. Badri, V. Davids, M. Pai, K. Dheda

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish (US)
Pages (from-to)1393-1397
Number of pages5
JournalEuropean Respiratory Journal
Volume38
Issue number6
DOIs
StatePublished - Dec 1 2011
Externally publishedYes

Keywords

  • HIV
  • Light-emitting diode microscopy
  • Smear microscopy
  • Tuberculosis

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

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