Opportunistic infections


Appropriate Tests


Immunodeficient patients are at particular risk of opportunistic infections and are also more susceptible to common pathogens.

An aggressive search for the responsible pathogen may include MCS urine (microscopy and culture), Blood culture, Aspiration of body fluids, Endoscopic brushings or biopsies, other tissue or organ biopsies (with lesions on diagnostic imaging); Cryptococcal Ag (serum); Cytomegalovirus Ab, Legionella Ab and Toxoplasma Ab.

Consult pathologist for assistance with defining the appropriate testing strategy.

See Immunodeficiency, Infection (increased susceptibility)

Viral infection


  • Cytomegalovirus infection


  • Herpes simplex virus infection


  • Varicella zoster infection


Bacterial infection


  • Mycobacterium tuberculosis

See Tuberculosis

  • Atypical mycobacteria

See Mycobacterial infection

  • Listeria monocytogenes

See Listeriosis

  • Legionella pneumophila

See Legionella infection

Fungal infection


  • Candida albicans

See Candidiasis

  • Cryptococcus neoformans

See Cryptococcal infection

  • Mucor sp

See Mucormycosis

  • Aspergillus spp

See Aspergillosis

  • Pneumocystis jiroveci

See Pneumocystis infection

Protozoal infection

  • Toxoplasma gondii

See Toxoplasmosis

  • Microsporidia

Ova cysts parasites faeces; examination for microsporidia must be specifically requested.

Helminthic infection

Ova cysts parasites faeces.

See also Worm infection

  • Strongyloides stercoralis

Faeces - microscopy of fresh specimen; Harada culture for larvae (consult pathologist); Strongyloides sp Ab.

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