An Innovative Test for the Rapid Detection of Specific IgG Antibodies in Human Whole-Blood for the Diagnosis of Opisthorchis viverrini Infection

Abstract

Chronic human liver fluke infections caused by Opisthorchis viverrini and Clonorchis sinensis can last for decades and cause liver and biliary diseases, including life-threatening pathology prior to cholangiocarcinoma (CCA). CCA generally has a poor prognosis. Serological diagnosis can support parasitological examination in diagnosing disease and screening for the risk of CCA. Here, we present an improved and innovative lateral flow immunochromatographic test (ICT) kit that uses whole-blood samples (WBS) rather than serum to diagnose human opisthorchiasis, which also successfully diagnosed human clonorchiasis. This ICT includes a soluble worm extract of O. viverrini adults and colloidal-gold-labeled conjugates of the IgG antibody to evaluate the diagnostic values with simulated WBS (n = 347). Simulated WBS were obtained by the spiking infection sera with red blood cells. The diagnostic sensitivity, specificity, positive and negative predictive values, and accuracy for detecting opisthorchiasis were 95.5%, 87.0%, 80.5%, 97.2%, and 90.1%, respectively. For clonorchiasis, these findings were 85.7%, 87.0%, 53.6%, 97.2%, and 86.8%, respectively. Combined for both diseases, they were 93.2%, 87.0%, 84.0%, 94.6%, and 89.6%, respectively. The ICT kit can possibly replace the ICT platforms for antibody detection in serum samples in field surveys in remote areas where sophisticated equipment is not available.

Keywords: IgG; clonorchiasis; immunochromatographic test kit; opisthorchiasis; point-of-care test; serodiagnosis; whole-blood sample.

Figure 1

(A) Schematic illustration of the OvB-test kit for the blood sample, and (B) the positive and negative results are shown with a reference board. A red band appears at the C line in the negative case (Hc) and two bands appear at the C and T lines in the opisthorchiasis (Ov). The reference color card positive for the IgG antibody level is also shown (cutoff 0.5 or more).

Figure 2

Representative results of the OvB- test kit using stimulated WBS from the healthy control (Hc), opisthorchiasis (Ov), clonorchiasis (Cs), and other parasitic diseases, including: (Al) ascariasis; (Tt) trichuriasis; (Gl) giardiasis; (Cp) capillariasis philippinensis; (Ac) angiostrongyliasis; (Tn) taeniasis saginata; (Se) sparganosis; (Bh) blastocystosis; (Gn) gnathostomiasis; (Hw) hookworm infections; (Ts) trichinosis; (Cc) cysticercosis; (Ss) strongyloidiasis; (Ph) paragonimiasis; (Fg) fascioliasis; and (MIF) minute intestinal fluke infections (lecithodendriid flukes). The intensity of the test line was visually estimated, according to the reference card. (S) indicates sample well.