Ordering Recommendation

Titers may aid in monitoring coccidioidomycosis (Valley fever) and treatment response. For initial establishment of diagnosis, refer to Coccidioides Antibodies Reflexive Panel (3001982).




Semi-Quantitative Complement Fixation




2-5 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Serum Separator Tube (SST).

Specimen Preparation

Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.4 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of acute specimens.

Storage/Transport Temperature


Unacceptable Conditions

Hemolyzed, icteric, or lipemic specimens.


Mark specimens plainly as "acute" or "convalescent."


After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)

Reference Interval

Less than 1:2

Interpretive Data

Any titer suggests past or current infection. However, greater than 30 percent of cases with chronic residual pulmonary disease have negative Complement Fixation (CF) tests. Titers of less than 1:32 (even as low as 1:2) may indicate past infection or self-limited disease; anticoccidioidal CF antibody titers in excess if 1:16 may indicate disseminated infection. CF serology may be used to follow therapy. Antibody in CSF is considered diagnostic for coccidioidal meningitis, although 10 percent of patients with coccidioidal meningitis will not have antibody in CSF.

Compliance Category



CF measures both IgM and IgG. As single antibody titers are generally not diagnostic, paired specimens are preferred. Acute and convalescent specimens (drawn at least 21 days apart), showing at least a fourfold rise in titer, are diagnostic.

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

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0050170 Coccidioides Antibody by CF 33380-7
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Cocci IgG, IgM CF
  • Coccidioidomycosis IgG/IgM
  • San Joaquin Fever Antibody
  • Valley Fever antibodies
Coccidioides Antibody by CF