Nematode Infections Workup

Updated: Jun 23, 2017
  • Author: Murat Hökelek, MD, PhD; Chief Editor: Mark R Wallace, MD, FACP, FIDSA  more...
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Laboratory Studies

Laboratory studies are as follows:

  • Stool examination for intestinal nematodes using native, zinc sulfate flotation, or formalin-ethyl acetate sedimentation techniques (based on characteristics of eggs or larvae in stool or adult worm, if passed; cellophane-tape impression for pinworms)
  • Examination of larvae or adult worms taken from the tissue, characteristic microfilariae on blood smear, eosinophilia
  • Filariasis - Membrane filtration technique, Knott technique, and thick blood smear (Giemsa stained)
  • Distinction of species by larval examination - Challenging and may require expert examination
  • Onchocerciasis - Identified by skin snip/biopsy showing larvae
  • Toxocariasis - Enzyme-linked immunosorbent assay (ELISA) and, occasionally, biopsy
  • Trichinosis - Muscle biopsy and ELISA
  • Anisakiasis - Latex-based agglutination, immunofluorescence, indirect hemagglutination, complement fixation, immunoblotting, and ELISA
  • Angiostrongyliasis (rat lungworm disease) - Eosinophilia in blood (>5%) or cerebrospinal fluid (CSF) (>10%) [2]

Imaging Studies

Imaging studies are as follows:

  • Larvae in sputum or adult worms observed on radiologic studies (uncommon)
  • Lung radiography for Löeffler syndrome
  • Ultrasonography - Useful in the diagnosis of ascariasis as a cause of biliary tract disease

Other Tests

Onchocerciasis: Skin snip, nodulectomy, slit-lamp examination, and Mazzotti test are helpful.


Histologic Findings

Characteristic eggs, worms, or larvae in tissue