Table 3.

Comparison of Laboratory Diagnostic Tests for Amebiasis

Method	Sensitivity, % [Reference]	Specificity, % [Reference]	Advantages	Disadvantages
Microscopy	<60% [4]	-	Widely available	Poor sensitivity and specificity; cannot differentiate from other Entamoeba spp.
			Screens for other parasites	Multiple stools need to be submitted
			Minimal equipment and reagents required	Skilled observer required; time-consuming
Serology	65%–92% [16]	>90% [16]	High sensitivity and specificity, useful adjunct to stool studies	Serology remains positive for years after resolution of infection, so less helpful in endemic areas; more useful in travelers
			Rapid turnaround	Antibody response is often detectable by the time of presentation but may need to be repeated in 7–10 days if initially negative
Stool antigen detection	0%–88% [42]	>80% [42]	May have high sensitivity in endemic areas but reduced sensitivity in nonendemic areas	Poor sensitivity for amebic liver abscess
			Simple to perform, rapid turnaround time, and commercially available combined tests exist to detect several enteroparasites	Requires fresh, not fixative preserved stool for analysis
PCR	92%–100% [42]	89%–100% [42]	Gold standard; high sensitivity and specificity for colitis and liver abscess with increasing availability	More expensive; cost may limit use in resource-limited settings
			Rapid turnaround; automated systems reduce technician time and risk of contamination	Requires analysis instruments, kits, and skilled technician
			Can be combined with multiplex panels to detect multiple enteric pathogens at a time

Abbreviation: PCR, polymerase chain reaction.