The major obstacles preventing better diagnosis are clinical suspicion and test availability. Doctors and health professionals need the 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 the unavailability of testing. There are several interconnected reasons for this:
GAFFI has identified the following five priority diseases and will work with partners to provide reliable and affordable diagnostic testing, in addition to skin NTDs:
Summary of current tests are shown here.
|Diagnostic||Ease of use||Equipment||Performance||Comments|
|Cryptococcal antigen LFAs||Simple, quick,||No||High and definitive||Double positive titre (> 1:160)Usually associated with meningitis|
|Pneumocystis PCR||Moderate||Yes||High||Freeze-dried kit now available.|
|Histoplasma antigen test||Moderate||Yes||High in AIDS||ELISA good, New LFA in clinical validation|
|Aspergillus IgG||Moderate||Yes||Very good, especially LFA||LFA now available. Multiple ELISA tests, some with limited sensitivity. Not fully evaluated in low resource countries.|
|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.|
The WHO’s Essential Diagnostic List which includes Cryptococcal, Histoplasma and Aspergillus antigen tests, Aspergillus antibody and Pneumocystis PCR tests, as well as blood culture, fungal culture, histopathology and direct microscopy.
Additional information, including manufacturers shown here.