Strongyloides – Serology

Specimen Collection and Handling

Specimen Requirements

Test Requested Required Requisition(s) Specimen Type Minimum Volume Collection Kit

Strongyloides serology, Strongyloides stercoralis, Strongyloidiasis

Whole blood or serum

5.0 ml whole blood or 1.0 ml serum

Vacutainer (SST)

Submission and Collection Notes

1

Indicate symptoms and date of onset on the General Test Requisition Form if diagnostic testing is required.

Limitations

Haemolysed, icteric, lipemic or microbially contaminated sera or plasma are not recommended for testing.

Accuracy of Strongyloides serology may be limited by cross-reactivity with other helminth co-infections, including schistosomiasis, toxocariasis, filariasis, and echinococcosis. Clinical correlation is suggested, along with parasitologic testing.

Manufacturer’s reported sensitivity and specificity 100%, respectively. Compared to the CDC Strongyliodes serologic assay, sensitivity is 100%, however, specificity is likely limited in the low-positive range of the assay.  An “indeterminate” range has been introduced, and an indeterminate result should be interpreted in the clinical context of the patient. A recent study on the diagnostic accuracy of 5 serologic assays for strongyloidiasis demonstrated a sensitivity of 91.2% (95% confidence interval 86.0-96.5%) and a specificity of 99.1% (95% confidence interval 97.4-100.0%) for this test.  Reference: PLoS NTDs 2014;8(1):e2640. Further assessment of performance characteristics in-house is ongoing.

Preparation Prior to Transport

Label the specimen container with the patient’s full name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.

Special Instructions

Centrifuge if using SST. Place specimen in biohazard bag and seal.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Strongyloides stercoralis IgG serology testing is performed once per week.

Turnaround time is up to 10 days from receipt by PHO laboratory.

Reporting

Results are reported to the ordering physician or health care provider as indicated on the requisition.

Test Methods

Strongyloides stercoralis IgG serology test is performed using an Enzyme Linked Immunosorbant Assay (ELISA).

Mis à jour le 21 déc. 2018