Entamoeba histolytica, the causative agent of amebiasis, is a pathogenic intestinal parasite. The E. histolytica test determines the presence or absence of specific serum antibodies to this parasite. Stool examination is considered the definitive diagnostic tool; however, the absence of detectable stool organisms does not necessarily rule out the disease. Antibiotic therapy, oil enemas, and barium may interfere with the ability to isolate this organism in the stool.
Collect a 7-mL blood serum sample in a red-topped tube. Observe standard precautions.
Label the specimen with the patient’s name, date, and test(s) ordered and place in a biohazard bag for transport to the laboratory.
Positive test (titer >1:128) indicates active or recent infection.
Amebic liver abscess and amebic dysentery indicate the presence of amebiasis.
Titers range from 1:256–1:2048 in the presence of current active amebiasis.
Titers <1:32 generally indicate an extraintestinal form of amebiasis.
A positive test may only reflect past but not current infections.
Pretest Patient Care
Explain test purpose and procedure.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Care
Review test results; report and record findings. Modify the nursing care plan as needed. Counsel the patient regarding abnormal results; explain the need for possible follow-up testing and treatment. See Interpreting Results of Immunologic Tests.
Follow guidelines in Chapter 1 for safe, effective, informed posttest care.