Strongyloidiasis laboratory findings: Difference between revisions
Jump to navigation
Jump to search
Aditya Ganti (talk | contribs) |
Aditya Ganti (talk | contribs) |
||
| Line 34: | Line 34: | ||
* A positive test warrants continuing efforts to establish a parasitological diagnosis followed by antihelminthic treatment. | * A positive test warrants continuing efforts to establish a parasitological diagnosis followed by antihelminthic treatment. | ||
* Serologic monitoring may be useful in the follow-up of immunocompetent treated patients: antibody levels decrease markedly within 6 months after successful chemotherapy. <ref>http://www.dpd.cdc.gov/dpdx/HTML/Strongyloidiasis.htm</ref> | * Serologic monitoring may be useful in the follow-up of immunocompetent treated patients: antibody levels decrease markedly within 6 months after successful chemotherapy. <ref>http://www.dpd.cdc.gov/dpdx/HTML/Strongyloidiasis.htm</ref> | ||
* More sensitive and specific serologic tests using recombinant antigens have been, and are being developed, and are available at specific laboratories. | |||
*An additional advantage to these serologic tests is that there is typically a significant drop in titer by 6 months after parasite eradication, which may make it possible to use these tests as a "test of cure."raph | |||
==References== | ==References== | ||
Revision as of 12:52, 21 June 2017
|
Strongyloidiasis Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Strongyloidiasis laboratory findings On the Web |
|
American Roentgen Ray Society Images of Strongyloidiasis laboratory findings |
|
Risk calculators and risk factors for Strongyloidiasis laboratory findings |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Laboratory Findings
Eosinophilia
Blood eosinophilia is generally present during the acute and chronic stages, but may be absent with dissemination.[1]
Stool Smaples
- The gold standard for the diagnosis of Strongyloides is serial stool examination.
- The diagnosis rests on the microscopic identification of larvae (rhabditiform and occasionally filariform) in the stool or duodenal fluid.
- Duodenal aspirate is more sensitive than stool examination, and duodenal biopsy may reveal parasites in the gastric crypts, in the duodenal glands, or eosinophilic infiltration in the lamina propria.
- Specialized stool exams include Baermann concentration, Horadi-Mori filter paper culture, quantitative acetate concentration technique, and nutrient agar plate cultures.
- The stool can be examined in wet mounts:
- Directly
- After concentration (formalin-ethyl acetate)
- After recovery of the larvae by the Baermann funnel technique
- After culture by the Harada-Mori filter paper technique
- After culturing in agar plates
- The duodenal fluid can be examined using techniques such as the Enterotest string or duodenal aspiration.
- In disseminated cases of strongyloidiasis, larvae can be detected in sputum by simple wet-mount in fluid from a bronchoalveolar lavage (BAL).
- Diagnostic characteristics: length 200 to 250 µm (up to 380 µm); buccal cavity short, and prominent genital primordium.
A: The prominent genital primordium in the mid-section of the larva (black arrow) is readily evident. Note also the Entamoeba coli cyst (white arrow) near the posterior end of the larva.
Antibody Detection
- Immunodiagnostic tests for strongyloidiasis are indicated when the infection is suspected and the organism cannot be demonstrated by duodenal aspiration, string tests, or by repeated examinations of stool.
- Antibody detection tests should use antigens derived from Strongyloides stercoralis filariform larvae for the highest sensitivity and specificity.
- Although indirect fluorescent antibody (IFA) and indirect hemagglutination (IHA) tests have been used, enzyme immunoassay (EIA) is currently recommended because of its greater sensitivity (90%).
- Immunocompromised persons with disseminated strongyloidiasis usually have detectable IgG antibodies despite their immunodepression.
- Cross-reactions in patients with filariasis and some other nematode infections can occur.
- Antibody test results cannot be used to differentiate between the past and current infection.
- A positive test warrants continuing efforts to establish a parasitological diagnosis followed by antihelminthic treatment.
- Serologic monitoring may be useful in the follow-up of immunocompetent treated patients: antibody levels decrease markedly within 6 months after successful chemotherapy. [2]
- More sensitive and specific serologic tests using recombinant antigens have been, and are being developed, and are available at specific laboratories.
- An additional advantage to these serologic tests is that there is typically a significant drop in titer by 6 months after parasite eradication, which may make it possible to use these tests as a "test of cure."raph