A few fungal diseases can be diagnosed clinically without any tests, but not many. Accurate diagnosis of fungal diseases is usually not straightforward. A new patient will be asked to give a history of the symptoms they have been experiencing. Depending on the history a number of laboratory tests may be ordered. These may well include the following tests.
Common combinations of tests to diagnose fungal disease:
|
Fungal problem |
Diagnostic performance |
|||||
|
|
Microscopy |
Agar culture |
X-rays/scans |
Antigen |
Blood antibody |
DNA detection |
|
Thrush (yeast infection) |
+++ |
+++ |
– |
– |
– |
– |
|
Candida bloodstream |
– |
+++ |
+ |
+ |
+ |
+++ |
|
Cryptococcal peritonitis |
+ |
+++ |
+ |
– |
– |
– |
|
Cryptococcal meningitis |
++ |
+++ |
+ |
+++ |
– |
– |
|
Invasive aspergillosis |
+ |
+ |
+++ |
++ |
– |
++ |
|
Chronic aspergillosis |
+ |
+ |
+++ |
– |
+++ |
++ |
|
Allergic aspergillosis (fungal asthma, cystic fibrosis) |
+ |
+ |
++ |
– |
+++ |
+ |
|
Coccidioidomycosis |
+ |
++ |
++ |
– |
+++ |
– |
|
Histoplasmosis |
+ |
++ |
+ |
++ |
++ |
– |
|
Mucormycosis |
+++ |
+ |
++ |
– |
– |
– |
The World Health Organisation has listed several diagnostic tests as Essential:
https://www.who.int/medical_devices/diagnostics/selection_in-vitro/en/
Direct microscopy
Blood culture
Histopathology
Fungal culture
Cryptococcal antigen (CrAg)
Histoplasma antigen
Aspergillus antigen
Aspergillus antibody
Pneumocystis PCR
Culture is important as this is a key means of determining the precise cause of an infection and finding out if antifungal resistance is present, but culture is s low and insensitive. The faster a positive diagnosis can be reached the better the outcome for the patient.