Hypersensitivity Pneumonitis

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Turnaround Time: 4 - 5 days
CPT Code:

86331; 86602(x2); 86606; 86609; 86671

Test Type: 1 mL Serum
Stability Time:



Room temperature

7 days


14 days


14 days

Freeze/thaw cycles

Stable x2

Reference Range:

Normal: negative


The test is used to detect the presence of precipitating antibodies associated with hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is an interstitial lung disease that is characterized by a complex immunological reaction of the lung parenchyma in response to repetitive inhalation and subsequent sensitization to a wide variety of inhaled organic dusts.1-7 HP is associated with progressive pulmonary disability, irreversible lung damage, and mortality in some cases. HP can be classified as Acute/Inflammatory (symptoms less than six months) and Chronic/Fibrotic (symptoms more than six months) based on clinical, radiologic and pathologic characteristics.8 The name previously used for this condition, extrinsic allergic alveolitis, has been largely abandoned because inflammation involves more than just the alveoli and can extend to the bronchioles as well. The severity of the disease and clinical presentation varies depending on the quantity and type of inhaled antigen causing the condition. Numerous antigens have been found to cause HP.

Diagnosis of HP can be challenging and requires a combination of detailed history, radiologic evaluation, pathological examination and laboratory testing. Acute exposures to inciting antigens typically cause abrupt onset of nonproductive cough, dyspnea, and chills with arthralgias or malaise within a few hours of heavy exposure to a specific antigen.1-4,8 Symptoms usually resolve within a few days of avoiding exposure. Coughing is a predominant symptom due to airway-centered nature of inflammation.Patients also report shortness of breath, malaise, weight loss. No single laboratory testis diagnostic for hypersensitivity pneumonitis.1,6-8 Double diffusion (Ouchterlony) assays are used to determine antigen-specific IgG antibodies. The appearance of precipitin arcs confirms the presence of precipitating antibodies to specific antigens.

A number of antigens have been found to cause HP but only a small proportion of the people who are exposed to these antigens develop HP.1-6,8,9 Exposures to the causative antigens can be associated with specific occupations or hobbies but can also occur in the home and general environment.

Bird or Pigeon Fancier’s Lung: Globally, this is the most commonly reported form of HP and is caused by exposure to organic antigens in bird (particularly pigeon) excreta.1,10,11 Indirect exposure from feather bedding or down comforters have also been reported to cause disease. Avian antigen can exist in the indoor environment regardless of antigen avoidance.12 The presence of avian antigen in the indoor environment can be attributed to wild birds found outdoors.12

Farmer’s Lung: Caused by exposure to moldy hay, compost or grain stored in conditions of high humidity in the agricultural workplace.2,13 IgG precipitins commonly associated with Farmer’s Lung including Aspergillus fumigatus, Thermoactinomyces sacchari, Thermoactinomyces vulgaris and Saccharopolyspora rectivirgula (formerly called Micropolyspora faeni).

Humidifier/Sauna Taker’s Lung: HP secondary to occupational exposure to moldy water from heating/ventilation/air-conditioning systems has been described in adults.14-16 Non-occupational exposure to molds including Aspergillus fumigatus and aureobasidium pullulans via home saunas or water damage has also been shown to cause HP.17-20

Early diagnosis of HP is critical to avoid the development of extensive pulmonary fibrosis or restrictive lung disease has occurred.1 Identification of the offending agentis critical in diagnosing HP and implementing preventive measures.5,7 If diagnosed early enough, complete avoidance of inciting antigen results in total recovery of lung function in the majority of patients. If not promptly diagnosed and treated, HP can progress to pulmonary fibrosis and progressive respiratory failure. Presence of fibrosis and honeycombing have been associated with higher mortality. Primary prevention should aim to reduce exposure to known organic antigens.

1. Greenberger PA. Hypersensitivity pneumonitis: A fibrosing alveolitis produced by inhalation of diverse antigens. J Allergy Clin Immunol. 2019 Apr;143(4):1295-1301. Epub 2018 Nov 15. PubMed 30448501

2. Costabel U, Bonella F, Guzman J. Chronic hypersensitivity pneumonitis. Clin Chest Med. 2012 Mar;33(1):151-163. PubMed 22365252

3. Lacasse Y, Girard M, Cormier Y. Recent advances in hypersensitivity pneumonitis. Chest. 2012 Jul;142(1):208-217. PubMed 22796841

4. Ohshimo S, Bonella F, Guzman J, Costabel U. Hypersensitivity pneumonitis. Immunol Allergy Clin North Am. 2012 Nov;32(4):537-556. PubMed 23102065

5. Patel AM, Ryu JH, Reed CE. Hypersensitivity pneumonitis: current concepts and future questions. J Allergy Clin Immunol. 2001 Nov;108(5):661-670. PubMed 11692086

6. Spagnolo P, Rossi G, Cavazza A, et al. Hypersensitivity Pneumonitis: A Comprehensive Review. J Investig Allergol Clin Immunol. 2015;25(4):237-250; quiz follow 250. PubMed 26310038

7. Jacobs RL, Andrews CP, Coalson JJ. Hypersensitivity pneumonitis: beyond classic occupational disease-changing concepts of diagnosis and management. Ann Allergy Asthma Immunol. 2005 Aug;95(2):115-128. PubMed 16136760

8. Vasakova M, Morell F, Walsh S, Leslie K, Raghu G. Hypersensitivity Pneumonitis: Perspectives in Diagnosis and Management. Am J Respir Crit Care Med. 2017 Sep 15;196(6):680-689. PubMed 28598197

9. Quirce S, Vandenplas O, Campo P. et al. Occupational hypersensitivity pneumonitis: an EAACI position paper. Allergy. 2016 Jun;71(6):765-779. PubMed 26913451

10. Woge MJ, Ryu JH, Moua T. Diagnostic implications of positive avian serology in suspected hypersensitivity pneumonitis. Respir Med. 2017 Aug;129:173-178. PubMed 28732828

11. Chan AL, Juarez MM, Leslie KO, Ismail HA, Albertson TE. Bird fancier's lung: a state-of-the-art review. Clin Rev Allergy Immunol. 2012 Aug;43(1-2):69-83. PubMed 21870048

12. Sema M, Miyazaki Y, Tsutsui T, Tomita M, Eishi Y, Inase N. Environmental levels of avian antigen are relevant to the progression of chronic hypersensitivity pneumonitis during antigen avoidance. Immun Inflamm Dis. 2018 Mar;6(1):154-162. PubMed 29168324

13. Cano-Jiménez E, Acuña A, Botana MI, et al. Farmer's Lung Disease. A Review. Arch Bronconeumol. 2016 Jun;52(6):321-328. PubMed 26874898

14. Woodard ED, Friedlander B, Lesher RJ, Font W, Kinsey R, Hearne FT. Outbreak of hypersensitivity pneumonitis in an industrial setting. JAMA. 1988 Apr 1;259(13):1965-1969. PubMed 3346977

15. Storms WW. Occupational hypersensitivity lung disease. J Occup Med. 1978 Dec;20(12):823-824. PubMed 569690

16. Baur X, Richter G, Pethran A, Czuppon AB, Schwaiblmair M. Increased prevalence of IgG-induced sensitization and hypersensitivity pneumonitis (humidifier lung) in nonsmokers exposed to aerosols of a contaminated air conditioner. Respiration. 1992;59(4):211-214. PubMed 1485005

17. Engelhart S, Rietschel E, Exner M, Lange L. Childhood hypersensitivity pneumonitis associated with fungal contamination of indoor hydroponics. Int J Hyg Environ Health. 2009 Jan;212(1):18-20. PubMed 18375180

18. Metzger WJ, Patterson R, Fink J, Semerdijan R, Roberts M. Sauna-takers disease. Hypersensitivity pneumonitis due to contaminated water in a home sauna. JAMA. 1976 Nov 8;236(19):2209-2211. PubMed 989816

19. Temprano J, Becker BA, Hutcheson PS, Knutsen AP, Dixit A, Slavin RG. Hyperse

Collection Details:

Collection Instructions:

Red-top tube or gel-barrier tube.

Room temperature.