Evaluation of patients suspected of having hypersensitivity pneumonitis (HP) induced by exposure to Micropolyspora faeni
Fluorescence Enzyme Immunoassay (FEIA)
M. faeni
Saccharopolyspora rectivirgula
S. rectivirgula
Hypersensitivity pneumonitis
Serum
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 0.5 mL
0.3 mL
Gross hemolysis | OK |
Gross lipemia | OK |
Gross icterus | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 21 days | |
Frozen | 21 days |
Evaluation of patients suspected of having hypersensitivity pneumonitis (HP) induced by exposure to Micropolyspora faeni
There are many antigens, both organic and inorganic, that have been associated with development of HP.(2) Causative organic antigens include a wide array of bacteria, mycobacteria, fungi, and animal proteins. Micropolyspora faeni is a bacteria sometimes found in moldy hay; farm or ranch workers may develop IgG antibodies against this antigen, which could lead to development of HP.
Clinical practice guidelines for HP include a diagnostic algorithm that focuses on exposure identification, imaging evaluation, and bronchoalveolar lavage/histopathology.(3) Detection of IgG antibodies specific for certain environmental antigens can help to document the causative exposure for an individual. This is critical, as an important treatment for these patients is antigen avoidance. However, IgG testing is only useful as supportive information for the diagnosis of HP; a positive result only indicates sensitization to the antigen and a negative result does not exclude the possibility that a patient with HP may be sensitized to another antigen.
0-12 years: < or =4.9 mg/L
13-18 years: < or =9.1 mg/L
>18 years: < or =13.2 mg/L
Positive results for IgG antibodies to Micropolyspora faeni, in patients with signs and symptoms of hypersensitivity pneumonitis, may be consistent with sensitization to this bacteria.
Negative results for IgG antibodies to M faeni do not exclude HP as a diagnosis; patients with clinical symptoms consistent with HP may be sensitized to a different antigen.
1. Sforza GG, Marinou A: Hypersensitivity pneumonitis: a complex lung disease. Clin Mol Allergy. 2017 Mar 7;15(6). doi: 10.1186/s12948-017-0062-7
2. Costabel U, Miyazaki Y, Pardo A, et al: Hypersensitivity pneumonitis. Nat Rev Dis Primers. 2020 Aug 6;6(1):65. doi: 10.1038/s41572-020-0191-z
3. Raghu G, Remy-Jardin M, Ryerson CJ, et al: Diagnosis of hypersensitivity pneumonitis in adults. An Official ATS/JRS/ALAT Clinical Practice Guideline. Am J Respir Crit Care Med. 2020 Aug1;202(3):e36-e69. doi: 10.1164/rccm.202005-2032ST
The Phadia CAP System specific IgG fluorescence enzyme immunoassay provides an in vitro method for measuring the concentration of circulating specific IgG antibodies in human blood samples. Specific IgG from the patient's serum reacts with the antigen of interest, which is covalently coupled to an ImmunoCAP. After washing away nonspecific IgG, enzyme labeled anti-IgG antibodies are added to form a complex. After incubation, unbound enzyme-anti IgG is washed away, and the bound complex is then incubated with a developing agent. After stopping the reaction, the fluorescence of the eluate is measured. The fluorescence is proportional to the amount of specific IgG, which is present in the patient's sample, ie, the higher the fluorescence value, the more specific IgG antibody is present.(Package insert: ImmunoCAP Micropolyspora. Phadia AB; 10/2019)
Monday through Friday
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
86609
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
MPSF | Micropolyspora faeni, IgG Ab, S | 26948-0 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
MPSF | Micropolyspora faeni, IgG Ab, S | 26948-0 |