01
Indications a clinician may consider parasitology evaluation for
Travel or residence in endemic regions
Time spent in regions with documented endemic transmission of parasitic infection, including travel for work, study, volunteering, or family visits, is a recognized indication for structured evaluation, particularly when symptoms followed exposure or when prior screening was not performed.
Immigration from endemic regions
Patients who immigrated from regions with endemic transmission of soil-transmitted helminths, schistosomiasis, Chagas disease, or strongyloidiasis may benefit from screening, including for infections that can remain asymptomatic for years.
Household contact with diagnosed cases
When a household member receives a parasitology diagnosis, evaluation of other household members may be considered depending on the organism, the route of transmission, and shared exposures.
Occupational and environmental exposure
Agricultural work, freshwater contact, soil contact, food handling, animal husbandry, and certain laboratory or healthcare roles can carry occupational exposure risk that warrants discussion.
Planned immunosuppression
Strongyloides screening before initiation of biologics, systemic corticosteroids, chemotherapy, or transplant immunosuppression is a defined indication. Untreated Strongyloides infection can progress to hyperinfection or disseminated disease under immunosuppression. This screening is often missed by oncology and rheumatology practices.
Unexplained eosinophilia
Persistent eosinophilia without an identified cause may prompt evaluation for tissue-invasive helminth infection, with the specific workup guided by exposure history.
Relevant symptoms not explained by prior evaluation
Symptoms such as persistent gastrointestinal disturbance after travel, migratory rash, or post-travel diarrhea that has not resolved with prior workup may warrant focused parasitology evaluation.
02
Tests that may be considered
Test selection follows published clinical guidance and the patient's exposure history. Specific panels are ordered by the consulting clinician.
Tier 1 — baseline panel
The basic tests every patient may get.
- CBC with differential
- Baseline hematology including the absolute eosinophil count.
- Comprehensive metabolic panel
- Baseline hepatic and renal function before any prescribed therapy.
- Strongyloides IgG ELISA
- Serologic screening for strongyloidiasis, recommended in CDC guidance prior to any planned immunosuppression.
- Stool ova and parasite, three specimens
- Direct microscopy. Sensitivity improves substantially with three separate collections.
- BioFire GI multiplex PCR
- FDA-cleared 22-target panel including Giardia, Cryptosporidium, and Entamoeba histolytica.
- Giardia antigen EIA
- Considered when symptoms suggest giardiasis.
- Pinworm cellophane-tape test
- Considered when Enterobius is plausible.
Tier 2 — exposure-targeted panels
Extra tests we order based on where you've been or what you've been around.
- Schistosoma IgG
- Considered for African, Middle Eastern, Brazilian, or Philippine freshwater exposure.
- Toxocara IgG
- Considered for pet ownership, pica history, or unexplained eosinophilia.
- T. cruzi (Chagas) two-step serology
- Considered per CDC guidance for Latin American residence or relevant US exposure.
- Echinococcus IgG with Western blot
- Considered for sheep or dog contact, or cystic imaging findings.
- Trichinella IgG
- Considered for raw pork or game consumption.
- Cysticercosis LLGP-EITB
- Considered for new-onset seizures with relevant exposure history.
- Leishmania rK39 or biopsy PCR
- Considered for non-healing ulcer with relevant travel history.
- Filarial antigen with timed blood smear
- Considered per CDC guidance for relevant exposure.
03
Imaging when clinically indicated
Abdominal ultrasound
Considered when hepatic or biliary involvement is clinically suspected, including in evaluation of hepatic cystic lesions consistent with echinococcosis.
Brain MRI with contrast
Considered for new-onset seizure or focal neurologic findings in patients with relevant exposure history, per IDSA and ASTMH neurocysticercosis guidance.
Cardiac echocardiogram
Considered in patients with confirmed Chagas disease for assessment of cardiomyopathy.
Whole-body MRI (optional partner offering)
An optional broader screening modality available through an imaging partner. Considered case by case and not part of the standard parasitology workup.