Volume 99, Issue 4
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



Appropriate diagnostic techniques are crucial to global soil-transmitted helminth (STH) control efforts. The recommended Kato–Katz method has low sensitivity in low-transmission settings. Quantitative polymerase chain reaction (qPCR) is a highly sensitive alternative diagnostic option. However, little is known about the variability in qPCR results, and there are few published comparisons between qPCR and other microscopy-based techniques such as sodium nitrate flotation (SNF). Using 865 stool samples collected from 571 individuals, we compared SNF and qPCR in terms of diagnostic sensitivity and infection intensity measurements. In addition, we conducted repeated examinations on a single –positive stool sample over a 6-month period. Results showed good diagnostic agreement between SNF and qPCR for spp. (κ = 0.69, < 0.001), and moderate agreement for hookworm (κ = 0.55, < 0.001) and spp. (κ = 0.50, < 0.001). Quantitative polymerase chain reaction demonstrated higher sensitivity than SNF for spp. (94.1% versus 68.1%) and hookworm (75.7% versus 66.9%) but not for spp. (53.1% versus 81.3%), which had very low prevalence. Sodium nitrate flotation and qPCR infection intensity measurements were strongly correlated for spp. (ρ = 0.82, < 0.001) and moderately correlated for hookworm (ρ = 0.58, < 0.001). Repeated examinations using qPCR showed that cycle threshold values decreased significantly at 1 month and remained stable thereafter. Results confirm the high diagnostic sensitivity of qPCR for spp. and hookworm, particularly for light-intensity infections, which is ideal for settings approaching transmission elimination. Results support the potential for qPCR to be used as a quantitative assay for STH. Further research is needed in settings where is endemic.


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  • Received : 26 Apr 2018
  • Accepted : 24 Jun 2018
  • Published online : 30 Jul 2018

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