HISTOPLASMA ANTIBODY IMMUNODIFFUSION

• Test Code

  321

• CPT Code

  86698

• Clinical Significance
  • The histoplasma antibody immunodiffusion test is used for the in vitro determination of precipitating antibodies to Histoplasma sp. It is also used as an aid in the diagnosis of Histoplasmosis.
  • This test detects the presence of two significant precipitin bands. Presence of both the H and the M band indicates active histoplasmosis. The presence of the M band alone indicates early or chronic disease. The M band may also be present following a recent histoplasmin skin test.
• Methodology

  Fungal Immunodiffusion

• Limitations

  The result is not intended to be used as the sole means for clinical diagnosis or patient management decisions.

  • Negative serologic tests may be observed among culturally demonstrable cases, which limits the predictive value of a negative test.
  • Negative serologic results obtained during the first month may warrant repeat testing.
  • Falsely negative results may be obtained when testing immunocompromised patients.
  • Test results cannot be used solely, to distinguish between active infection and prior exposure.
• Specimen Collection

  Serum: Collect serum specimens in serum separator or red top tube. Allow blood to clot for 30 minutes, then centrifuge. Pipette serum into a plastic screw cap vial.

• Minimum Specimen Requirements

  Serum: 0.25 mL per antibody

• Specimen Stability
  • Refrigerated: 14 days
  • Frozen: 6 months
• Specimen Rejection

  Any specimen types other than serum.

• Transport Temperature

  Refrigerated/Frozen

• Shipping

  Ship on dry ice to arrive Monday‐Friday using a next day delivery service. Frozen ice packs may be substituted if sample is shipped the day of collection.

• Turnaround Time

  Testing performed Tuesdays and Fridays.

  Serum: TAT 3 days from setup

• Reference Range
  • Antibody not detected
  • Will report H and M bands
• Interpretative Information
  • Negative: Antibody not detected
  • Positive: Antibody detected