Interpretive Handbook

Test 82514 :
Thermoactinomyces vulgaris, IgG Antibodies, Serum

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Thermoactinomyces vulgaris is one of the causative agents of hypersensitivity pneumonitis (HP). Other causative microorganisms include Micropolyspora faeni and Aspergillus fumigatus. The development of HP caused by Thermoactinomyces vulgaris is accompanied by an immune response to Thermoactinomyces vulgaris antigens with production of IgG antibodies. While the immunopathogenesis of HP is not known, several immune mechanisms are postulated to play a role, including both cellular and humoral mechanisms.(1)

Useful For Suggests clinical disorders or settings where the test may be helpful

Evaluation of patients suspected of having hypersensitivity pneumonitis induced by exposure to Thermoactinomyces vulgaris

Interpretation Provides information to assist in interpretation of the test results

Elevated concentrations of IgG antibodies to Thermoactinomyces vulgaris, Aspergillus fumigatus, or Micropolyspora faeni in patients with signs and symptoms of hypersensitivity pneumonitis may be consistent with disease caused by exposure to 1 or more of these organic antigens.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

IgG antibodies to Thermoactinomyces vulgaris, Aspergillus fumigatus, or Micropolyspora faeni may be found in sera from healthy individuals; the presence of these specific antibodies is not sufficient to establish the diagnosis of hypersensitivity pneumonitis (HP).


The concentrations of antibodies to these antigens may decrease following treatment, although elevated concentrations may persist in treated patients.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

0-12 years: < or =6.6 mg/L

13-18 years: < or =11.0 mg/L

>18 years: < or =23.9 mg/L

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Fink JN, Zacharisen MC: Chapter 69: Hypersensitivity pneumonitis. In Allergy Principles and Practice. Vol 1. Fifth edition. Edited by E Middleton Jr, CE Reed, EF Ellis, et al. St. Louis, MO, Mosby Year Book Inc., 1998

2. Girard M, Lacasse Y, Cormier Y: Hypersensitivity pneumonitis. Allergy 2009;64:322-334

3. Grunes D, Beasley MB: Hypersensitivity pneumonitis: A review and update of histologic findings. J Clin Pathol 2013;66:888-895