A C van Wyk1, B J Marais, R M Warren, S S van Wyk, C A Wright. 1. Division of Anatomical Pathology, Department of Pathology, National Health Laboratory Service, Stellenbosch University, Cape Town, South Africa. avw@sun.ac.za
Abstract
BACKGROUND: Fine-needle aspiration biopsy (FNAB) is a simple, safe and effective method for investigating suspected mycobacterial lymphadenitis in children. Fluorescence microscopy can provide rapid mycobacterial confirmation. Light-emitting diodes (LEDs) provide a cheap and robust excitation light source, making fluorescence microscopy feasible in resource-limited settings. OBJECTIVE: To compare the diagnostic performance of LED fluorescence microscopy on Papanicolaou (PAP) stained smears with the conventional mercury vapour lamp (MVL). METHODS: FNAB smears routinely collected from palpable lymph nodes in children with suspected mycobacterial disease were PAP-stained and evaluated by two independent microscopists using different excitatory light sources (MVL and LED). Mycobacterial culture results provided the reference standard. A manually rechargeable battery-powered LED power source was evaluated in a random subset. RESULTS: We evaluated 182 FNAB smears from 121 children (median age 31 months, interquartile range 10-67). Mycobacterial cultures were positive in 84 of 121 (69%) children. The mean sensitivity with LED (mains-powered), LED (rechargeable battery-powered) and MVL was respectively 48.2%, 50.0% and 51.8% (specificity 78.4%, 86.7% and 78.4%). Inter-observer variation was similar for LED and MVL (κ = 0.5). CONCLUSION: LED fluorescence microscopy provides a reliable alternative to conventional methods and has many favourable attributes that would facilitate improved, decentralised diagnostic services.
BACKGROUND: Fine-needle aspiration biopsy (FNAB) is a simple, safe and effective method for investigating suspected mycobacterial lymphadenitis in children. Fluorescence microscopy can provide rapid mycobacterial confirmation. Light-emitting diodes (LEDs) provide a cheap and robust excitation light source, making fluorescence microscopy feasible in resource-limited settings. OBJECTIVE: To compare the diagnostic performance of LED fluorescence microscopy on Papanicolaou (PAP) stained smears with the conventional mercury vapour lamp (MVL). METHODS: FNAB smears routinely collected from palpable lymph nodes in children with suspected mycobacterial disease were PAP-stained and evaluated by two independent microscopists using different excitatory light sources (MVL and LED). Mycobacterial culture results provided the reference standard. A manually rechargeable battery-powered LED power source was evaluated in a random subset. RESULTS: We evaluated 182 FNAB smears from 121 children (median age 31 months, interquartile range 10-67). Mycobacterial cultures were positive in 84 of 121 (69%) children. The mean sensitivity with LED (mains-powered), LED (rechargeable battery-powered) and MVL was respectively 48.2%, 50.0% and 51.8% (specificity 78.4%, 86.7% and 78.4%). Inter-observer variation was similar for LED and MVL (κ = 0.5). CONCLUSION:LED fluorescence microscopy provides a reliable alternative to conventional methods and has many favourable attributes that would facilitate improved, decentralised diagnostic services.
Authors: Chifumbe Chintu; Victor Mudenda; Sebastian Lucas; Andrew Nunn; Kennedy Lishimpi; Daniel Maswahu; Francis Kasolo; Peter Mwaba; Ganapati Bhat; Hiroshi Terunuma; Alimuddin Zumla Journal: Lancet Date: 2002-09-28 Impact factor: 79.321
Authors: Colleen A Wright; Mirjam van der Burg; D Geiger; Jeroen G Noordzij; Steven M Burgess; Ben J Marais Journal: Diagn Cytopathol Date: 2008-04 Impact factor: 1.582
Authors: K Bissell; A D Harries; A J Reid; M Edginton; S G Hinderaker; S Satyanarayana; D A Enarson; R Zachariah Journal: Public Health Action Date: 2012-09-21