ARUP's Laboratory Test Directory

Histoplasma Antibodies by CF : 0050625

Mnemonic: HISTO

Methodology: Semi-Quantitative Complement Fixation
Performed: Sun-Sat
Reported: 1-3 days
Specimen Required: Collect: Serum separator tube.

Specimen Preparation: Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.25 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of acute specimens. Mark specimens plainly as acute or convalescent.

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Contaminated or severely lipemic specimens.

Stability (collection to initiation of testing): After separation from cells: Ambient: 48 hours; 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 percent 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 percent of cases.
Note: Negative fungal serology does not rule out the possibility of current infection.
CPT Code(s): 86698 x2