Diagnostic Deficiencies

The major obstacles preventing better diagnosis are clinical suspicion and test availability. Doctors and health professionals need education to consider a fungal diagnosis, and it is usually not clinically obvious. Many fungal diagnostic tests are insensitive, some are not specific and large parts of the world have none.

The largest problem for most of the global population is simply unavailability of testing. There are several interconnected reasons for this:

  1. A lack of trained personnel to undertake the tests
  2. Low prioritization of fungal infection by many healthcare organizations and health ministries
  3. Poor distribution channels for appropriate diagnostics because of a lack of demand
  4. Expensive tests
  5. Inappropriate test formats for rural and low resource environments
  6. No laboratory facility and limited or intermittent electricity supply
  7. Lack of standardization and validation of tests in different countries leading to uncertainty about diagnostic performance.

GAFFI has identified the following five priority diseases and will work with partners to provide reliable and affordable diagnostic testing:

  • Cryptococcal meningitis in AIDS .  View article “Addressing Cryptococcal Infection in Africa
  • Pneumocystis pneumonia in AIDS, cancer and other groups
  • Histoplasmosis in AIDS and other groups (most common in the Americas)
  • Chronic pulmonary aspergillosis following TB and other pulmonary diseases
  • Fungal keratitis
Dissemination of diagnostics is also a key aim.

Summary of current tests are shown here.

Diagnostic Ease of use Equipment Performance Deficiencies
Cryptococcal antigen LFAs Simple, quick, No High and definitive Double positive titre (> 1:160)Usually associated with meningitis
Pneumocystis PCR Moderate Yes High Needs to be put on a low cost platform. Simpler simple processing required.
Histoplasma antigen test Moderate Yes High in AIDS ELISA good, New LFA in clinical validation
Aspergillus IgG Moderate Yes Good, needs development Multiple tests available, some with limited sensitivity. Not fully standardised or evaluated in low resource countries. Simple dipstick for blood would be much better.  Comparisons published.
Microscopy and culture Difficult Yes, simple Moderate (slow), if staff well trained. Otherwise low. Microscopy requires skill. and a direct detection tool would be much superior. Culture is simple, but lab contamination problematic and culture interpretation difficult. PCR or antigen tests would be superior.


Additional information, including manufacturers shown here.