Molecular diagnosis
In reference diagnosis laboratories, PCR is the method of choice for discriminating between the pathogenic species (E. histolytica) from the nonpathogenic species (E. dispar).

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A:  Agarose gel (2%) analysis of a PCR diagnostic test for differentiation between E. histolytica and E. dispar.

• Lanes 1 - 4: Amplification with the Psp3/Psp5¹ PCR primer pair specific for E. histolytica.  Diagnostic band size - 876 bp.
• Lanes 6 - 9: Amplification with the NPsp3/NPsp5¹ PCR primer pair specific for E. dispar.  Diagnostic band size - 876 bp.
• Lanes 1 and 6: E. histolytica 200:NIH, zymodeme II (positive control for E. histolytica).
• Lanes 2 and 7: E. dispar 351:IMMiT, zymodeme I (positive control for E. dispar).
• Lanes 3 and 8: Specimen from a patient with a liver abscess (positive with E. histolytica primers and negative with E. dispar primers).  E. histolytica 333:IMMiT, zymodeme XIV.
• Lanes 4 and 9: Specimen from an asymptomatic patient (positive with E. dispar primers and negative with with E. histolytica primers).  E. dispar 389:IMMiT, zymodeme I.
• Lane 5: Molecular base pair standard, 100-bp ladder (from 600 to 1,000 bp).

Figure contributed by Assist. Prof. Przemyslaw Myjak, Ph.D., Institute of Maritime and Tropical Medicine, Gdynia, Poland.

Reference:

Clark CG, Diamond LS. Differentiation of pathogenic Entamoeba histolytica from other intestinal protozoa by riboprinting. Arch Med Res 1992;23:15-16.