Test Details
Methodology
Double immunodiffusion (DID)
Result Turnaround Time
2 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
Antibody titers for mycelial and yeast antigens of Histoplasma
Use
Immunodiffusion test is used to detect antibodies to Histoplasma capsulatum. The antigen used is a culture filtrate. Histoplasmin H and M preciptins can be identified by the assay. The M band often appears first and may occur without the H band. M preciptin is found in about 70% of both acute and chronic histoplasmosis cases. Both M and H occur together in only about 10% of patients. Results should be interpreted in the context of clinical presentation and other laboratory findings (e.g., fungal culture).
Limitations
Negative fungal serology does not rule out the possibility of current infection.
Specimen Requirements
Specimen
Serum
Volume
0.6 mL
Minimum Volume
0.25 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube or gel-barrier tube
Stability Requirements
Temperature | Period |
|---|---|
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x2 |
Reference Range
Negative: <1:1
Storage Instructions
Refrigerate
Causes for Rejection
Hemolysis; lipemia; gross bacterial contamination
References
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 164319 | Histoplasma Abs, Qn, DID | 27266-6 | 164320 | Histoplasma Abs, Qn, DID | 27266-6 | |
| Order Code | 164319 | |||||
| Order Code Name | Histoplasma Abs, Qn, DID | |||||
| Order Loinc | 27266-6 | |||||
| Result Code | 164320 | |||||
| Result Code Name | Histoplasma Abs, Qn, DID | |||||
| UofM | ||||||
| Result LOINC | 27266-6 |