In diagnosis: Laboratory tests Laboratory tests can be valuable aids in making a diagnosis, but, as screening tools for detecting hidden disease in asymptomatic individuals, their usefulness is limited. The value of a test as a diagnostic aid depends on its sensitivity and specificity.

1. LABORATORY DIAGNOSIS OF
FUNGI
BY : ANJALI SHARMA (M.Sc.)
DEPARTMENT OF MICROBIOLOGY

2. CONTENTS:
1. DIRECT MICROSCOPY
2. CULTURE MEDIA
3. DNA PROBES
4. SEROLOGICAL TESTS

3. 1)DIRECT
MICROSCOPY
 Collection of samples – from skin scrapping, nails
scrabs ,sputum etc .)
 Morphology : conidia , filamentousspores , ( asexual ,
sexual ) hyphae etc . In light microscope .
 Includes different dyes :
1. 10%KOH SOLUTION:
 To dissolve tissue material.
 Alkali resistance fungi intact or stained with special
dye.
 E.g: indian ink – for identification of cryptococcus .

4. 2. CALCOFLOUR WHITE :
 Bind to cell wall of fungi.
3. METHAMINE SILVER :
 Diagnosis of fungi in tissue.

5. CULTURE
MEDIA:
1. SABOURAUD’S DEXTROSE AGAR:
 Facilitates slow growing fungi appearance.
 Bacteria can’t grow on this agar , beacuse of the low
pH.
And presence of antibiotics.

6. DNAPROBES:
 Visual identify of colony growing in culture at earlier
stage of growth.
 Diagnosis made rapid .
 DNA PROBE TEST : cryptococcus, blastomyces .

7. SEROLOGICAL
TESTS:
1. PRESENCE OF ANTIBODIES :
2. Presence of antibodies in patients’ serum or spinal
fluid used for – systemic mycoses .
 It is not uselful for other kind of mycoses .
2. COMPLIMENT FIXATION:
 E.g.: histoplamosis , blastomycosis ,coccidiomycoses .
3. AGGLUTINATION TESTS :
 E.g. : Cryptomycoses .
 Polysaccharide capsular antigens detected in C.
Neoforms .