ARUP's Laboratory Test Directory

0050625: Histoplasma Antibodies by CF

Test Mnemonic: HISTO
Methodology: Complement Fixation

Performed: Sun-Fri

Reported: 2-4 days

Specimen Required:  
Collect: One 4 mL SST.

Transport: 1 mL serum at 2-8°C. (Min: 0.5 mL)  Submit specimen in an ARUP Standard Transport Tube.

Pediatric Collection/Transport: 0.3 mL serum at 2-8°C.

Remarks: Separate serum from cells ASAP. Acute and convalescent specimens must be labeled as such; parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of acute specimens. Please mark specimens plainly as "acute" or "convalescent."

Unacceptable Conditions: Severely lipemic or contaminated specimens.

Stability: After separation from cells: Ambient: 2 days; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)

Reference Interval:
 
Test Number Components Reference Interval
 Histoplasma Mycelia Antibody by CF < 1:8
 Histoplasma Yeast Antibody by CF < 1:8

Interpretive Data:
An antibody titer greater than or equal to 1:8  is generally considered presumptive evidence of histoplasmosis. Greater than 1:32 or rising titers indicate strong presumptive evidence of histoplasmosis.

Yeast phase is regarded as more sensitive. Approximately 90-95% of cases have positive titers to one or both antigens. Titers to mycelial antigen are higher in chronic infection. Cross-reactions, usually at lower titers, may occur with other fungal disease. Rising titers suggest progression of infection. Skin tests in individuals previously exposed may cause titer elevation in 17-20% of cases.



Note:
Negative fungal serology does not rule out the possibility of current infection.

CPT Code(s):
86698 Histoplasma  mycelia; 86698 Histoplasma  yeast