This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Investigations

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

Seek expert advice.

Laboratory investigations:

  • microscopic examination for schistosome eggs - should be carried out at least two months after the last known fresh water contact
    • in stools
      • by observing even a single egg in thick smears of stool specimens (2-10 mg) with or without suspension in saline
      • as many as three specimens may be needed to make a diagnosis in some patients
      • rapid, simple, and inexpensive Kato-Katz thick smear stool examination
        • recommended by WHO for intestinal schistosomiasis when the intensity of infection is high
        • requires 40-50 mg of faeces
        • has specificity of 100% but its sensitivity varies with prevalence and intensity of infection, as well as with the number of stool specimens collected and slides prepared for microscopy.
    • in urine
      • S haematobium eggs can be detected on microscopy in a urine sample concentrated by sedimentation, centrifugation, or filtration and forced over a paper or nitrocellulose filter
      • urine should ideally be collected when there is maximum excretion of eggs - between 10am-2pm
  • PCR based assays for detection of schistosome DNA in faeces or sera and plasma
  • biopsy of bladder or rectal mucosa - may be useful for diagnosis in patients with a typical clinical presentation of schistosomiasis in the absence of eggs in urine or faeces
  • serological assays
    • detects antibodies against schistosomal antigens
    • most techniques detect IgG, IgM, or IgE against soluble worm antigen or soluble egg antigen by enzyme-linked immunosorbent assay (ELISA), indirect haemagglutination, or immunofluorescence.
    • useful for symptomatic travellers, but for people in endemic regions serology cannot differentiate between active infection and past exposure
    • positive test may be diagnostic in patients who are not excreting eggs e,g - Katayama syndrome
  • additional supportive laboratory evidence of schistosomiasis include:
    • eosinophilia (>80% of the patients) with acute infections
    • anaemia and thrombocytopenia - in chronic and advanced disease
    • increased prothrombin time is indicated by an increased INR - may be seen in chronic and advanced disease
    • hypoalbuminaemia
    • raised concentrations of urea and creatinine
    • hypergammaglobulinaemia and hypoalbuminaemia - in chronic and advanced disease (1,2)

Radiology

  • chest radiography
    • pulmonary infiltrates can be seen in acute cases (Katayama syndrome)
  • abdominal ultrasound
    • can establish extent of liver and spleen pathology in intestinal schistosomiasis
  • pelvic ultrasound
    • useful in urinary schistosomiasis to identify the extent of bladder, ureteral and renal pathology (1,2)

Additional investigations:

  • cystoscopy - reveals characteristic "sandy patches" (1)
  • abdominal X-ray - bladder calcification
  • intravenous urogram - may demonstrate hydro-ureter, hydronephrosis or filling defects in the bladder

Reference:

Create an account to add page annotations

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.