Evaluation of Low Concentration Normal Saline Technique for Microfilaria Detection in Migrant Workers at PakTho Hospital, Ratchaburi Province

Abstract

Elephantiasis in Thailand is caused by filarial nematodes; Wuchereria  bancrofti  and

Brugia  malayi  which are spreading world-wide  including among migrant workers in Thailand. This study aimed to evaluate the use of the newly developed low concentration normal saline technique (LNSS technique) for detection of microfilaria in migrant workers at PakTho Hospital, Ratchaburi Province. A total of 1,967  blood samples collected from migrant workers at PakTho Hospital in 2016 were screened for microfilaria by thick smear, buffy coat capillary tube  and LNSS  technique.  The  results  showed  that 56  (2.8%)  positive  microfilaria  cases were detected by LNSS technique but not by the thick smear and the buffy coat capillary tube methods. Comparison between LNSS technique and microfilaria confirmatory test showed that the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were

100%, 100%, 100%, 100% and 100%, respectively. In conclusion, LNSS technique is easy, inexpensive  and efficient  for  the microfilaria screening  test.  This technique should  provide a suitable alternative method that can be applied to screen microfilaria in immigrant workers.