Fungal – Serology
|Test Requested||Required Requisition(s)||Specimen Type||Minimum Volume||Collection Kit|
Blood or serum
5.0 ml blood or 1.0 ml serum
Blood, clotted - vacutainer tubes (SST)
Submission and Collection Notes
Timing of Specimen Collection
An acute serum (collected early after the onset of symptoms) and a convalescent (collected 2-3 weeks later) may be required for laboratory diagnosis. Please see “Limitations of the Procedure” below, under Additional Information.
Haemolysed, icteric, lipemic or microbially contaminated sera or plasma are not recommended for testing.
Preparation Prior to Transport
Label the specimen container with the patient’s full name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.
Centrifuge if using SST. Place specimen in biohazard bag and seal.
Test Frequency and Turnaround Time (TAT)
Fungal Immunodiffusion and Complement Fixation testing is performed once per week.
Turnaround time is up to 10 days from receipt by PHO Laboratory.
Results are reported to the ordering physician or health care provider as indicated on the requisition.
Complement fixation (CF) test is performed for the detection of antibodies to Histoplasma capsulatum, Blastomyces dermatitidis and Coccidioides immitis. A positive serologic response may take more than 4 weeks to develop. Sensitivity is poor for blastomycosis, 70-90% at 6 weeks post-infection for histoplasmosis and up to 90% for coccidioidomycosis. Cross-reactions among these three fungi may occur, reducing the specificity of the tests
Immunodiffusion (ID) test is performed for the detection of antibodies to H. capsulatum, B. dermatitidis, C. immitis and Aspergillus species
Aspergillus ID test: Demonstration of one or more precipitin bands against Aspergillus antigen is presumptive evidence of colonization or allergy to an Aspergillus species. This test may be useful in the diagnosis of allergic bronchopulmonary aspergillosis, but is not helpful in the diagnosis of invasive aspergillosis.
B. dermatitidis ID test: A positive test (A band) provides presumptive evidence of infection. A negative test does not exclude the existence of active blastomycosis.
C. immitis ID test: A positive test (F band) is presumptive evidence of C. immitis infection. A negative test does not exclude coccidioidomycosis.
H. capsulatum ID test: A positive test (H and/or M band) provides presumptive evidence of infection. H band is indicative of acute infection, whereas M band is positive in prior infections, and both acute and chronic disease. A negative test does not exclude the existence of histoplasmosis.