Multicentre evaluation of Ziehl-Neelsen and light-emitting diode fluorescence microscopy in China

To assess the feasibility of using light-emitting diode fluorescence microscopy (LED-FM) in peripheral laboratories in China.

The performance of LED-FM and Ziehl-Neelsen (ZN) microscopy was compared on slides directly prepared from the sputum of tuberculosis (TB) suspects and follow-up patients on treatment. The examination time, fading of fluorescence-stained slides, average unit cost and qualitative user appraisal of LED-FM were also analysed.

Among 11 276 slides, the smear-positive rate for LED-FM was 11.2% (1263/11 276), 2.6% (294/11 276) higher than that of ZN (8.6%, 969/11 276; χ(2) 263.5, P < 0.05). The examination time for LED-FM (120.0 ± 38.9 seconds) was shorter than that for ZN (206.3 ± 75.9 s; t = 28.12, P < 0.05). For smear fading, quantitative and qualitative errors occurred within respectively 7.8 and 7.7 weeks. The average unit costs for ZN and LED-FM were respectively US$2.20 ± 0.58 and US$1.97 ± 0.71 (t = 5.08, P < 0.05). LED-FM was accepted by most laboratory technicians.

LED-FM compared favourably with ZN, with a higher smear-positive detection rate, a shorter examination time and lower unit examination cost. LED-FM may be an alternative to ZN as a cost-effective method for detecting bacilli in peripheral laboratories in China.