Comparison of the Kato-Katz, Wet Mount, and Formol-Ether Concentration Diagnostic Techniques for Intestinal Helminth Infections in Ethiopia

Table 2

Wet mount, Kato-Katz, and FEC techniques results compared to the gold standard by species of common helminthes from students of Atse Fasil General Elementary School, Northwest Ethiopia, March 10–June 30, 2008.

Parasite	Technique	Infected students no. (%)	NPV (95% CI)	Sensitivity (95% CI)
S. mansoni	Gold standard	154 (43.5)
	Kato katz	148 (41.8)	97.1% (0.95–0.97)	96.1% (0.94–0.96)
	FEC	90 (25.4)	75.8% (0.74–0.75)	58.4% (0.55–0.58)
	Wet mount	34 (9.6)	62.5% (0.61–0.62)	22.1% (0.194–0.221)
A. lumbricoides	Gold standard	102 (28.8)
	Kato-Katz	95 (26.8)	97.3% (0.95–0.97)	93.1% (0.89–0.93)
	FEC	83 (23.4)	93.0% (0.92–0.93)	81.4% (0.77–0.81)
	Wet mount	53 (15)	83.7% (0.82–0.83)	52.0% (0.48–0.52)
T. trichiura	Gold standard	64 (18.1)
	Kato-Katz	58 (16.4)	98.0% (0.97–0.98)	90.6% (0.85–0.91)
	FEC	37 (10.5)	91.5% (0.90–0.92)	57.8% (0.52–0.58)
	Wet mount	8 (2.3)	83.8% (0.83–0.84)	12.5% (0.07–0.12)
Hook worm	Gold standard	29 (8.2)
	Kato-Katz	20 (5.6)	97.3% (0.96–0.97)	69.0% (0.57–0.69)
	FEC	21 (5.9)	97.6% (0.97–0.98)	72.4% (0.60–0.72)
	Wet mount	11 (3.1)	94.8% (0.94–0.95)	37.9% (0.27–0.38)

FEC: formol-ether concentration, NPV: negative predictive value.