Recommended Medical Screening Protocol
For people exposed to work-related allergens
Except for workers exposed to formaldehyde (Rule 325.51451-.51477),
there are no legal requirements to perform medical surveillance
on individuals exposed to occupational allergens (View a list of common workplace allergens). The Michigan
Occupational Safety and Health Administration's (MIOSHA) Respiratory
Protection Standard 1910.34 (e) (1) states that the employer
shall provide a medical evaluation to determine the employee’s
ability to use a respirator, before the employee is fit tested
or required to use the respirator in the work place.
Annual medical examinations for individuals who are potentially exposed
to occupational allergens is good medical practice. It has been
well documented that the longer an individual remains exposed to
an occupational allergen that he/she has become sensitized to,
the more likely that he/she will have persistent breathing
problems even after exposure has ended (go to the bottom of this
page for a listing of relevant articles from the medical literature).
The purpose then of an annual medical screening is to identify
symptomatic individuals and remove them from exposure so as to
reduce the likelihood of causing a chronic disability.
Studies in the medical literature do not support excluding individuals
with an allergic disposition (family or personal history) or
cigarette smokers identified in a pre-placement physical, from
working around occupational allergens. The dose that an
individual inhales from both usual daily exposure and
non-routine heavy exposures from spills is the best predictor of
who will become symptomatic.
Accordingly, medical surveillance is NOT a substitute for good
dust and chemical control in the work place. Controlling
exposure is the only effective primary prevention strategy.
1) Questionnaire – A standardized questionnaire should be administered.
A questionnaire should be administered during a pre-placement
physical to obtain a baseline and on an annual basis. Since the
symptoms from occupational allergens can be intermittent
particularly when they first begin, the person may have a
completely normal physical examination and breathing test and
still be having severe attacks of asthma. Click here to find
key questions that should be included at an
initial and annual examination.
2) Physical examination – A physical examination with particular attention to the skin, head, eyes, ears, nose,
throat, and lungs should be performed pre-placement as a baseline and on an annual basis.
3) Pulmonary function testing should be done as a baseline and
annually. All pulmonary function testing should use equipment
and follow the protocol of the American Thoracic Society1.
The technician administering the test should have completed an
accredited training course such as one approved by the National
Institute for Occupational Safety and Health.
It is important not only to evaluate the latest pulmonary function
test as to whether it is normal or abnormal, but also to observe
excessive loss between successive years. Studies on isocyanate
exposure have suggested excessive loss (>25-35 ml per year) as a
potential adverse effect, even in the absence of symptoms of
Individuals who are suspected to have occupational asthma should
have the diagnosis confirmed by pre and post shift or mid shift
(depending when the individual becomes symptomatic) pulmonary
function testing or measurement of peak flow every two hours
over a two-week period with a portable peak flow meter.
Sufficient time off work (two weeks or more) may be necessary to
allow recovery and documentation by peak flow measurements.
Individuals with confirmed work-related asthma should, whenever
possible, be given the option of transfer to areas of
non-exposure. ; Sensitized individuals may react at extremely low
levels of exposure. In order for this transfer option to be a
realistic alternative, the individuals should be able to
maintain his/her pay rate at the new job.
All individuals should be strongly advised to stop smoking. For
exposures to some substances, smokers with similar levels of
exposure as nonsmokers will develop work-related asthma at
higher rates and in a shorter period of time than non-smokers.
||American Thoracic Society. Standardization of Spirometry – 1994 Update.
American Journal of Respiratory and Critical Care Medicine 1995;
|| Yassi A.
Occupational Health Program, University of Manitoba, Winnipeg,
Canada. Health and socioeconomic consequences of occupational
respiratory allergies: a pilot study using workers' compensation
data. American Journal of Industrial Medicine
View abstract on PubMed.
||Mapp CE, Corona
PC, De Marzo N, Fabbri L. Institute of Occupational Medicine,
University of Padova, Italy. Persistent asthma due to
isocyanates. A follow‑up study of subjects with occupational
asthma due to toluene diisocyanate (TDI). American Review
of Respiratory Disease 1988 Jun;137(6):1326-9.
View abstract on PubMed.
||Malo JL, Cartier A, Ghezzo H, Lafrance M, McCants M, Lehrer SB. Department of Chest
Medicine, Hopital du Sacre‑Coeur, Montreal, Canada. Patterns of
improvement in spirometry, bronchial hyperresponsiveness, and
specific IgE antibody levels after cessation of exposure in
occupational asthma caused by snow‑crab processing.
American Review of Respiratory Disease 1988 Oct;138(4):807-12.
View abstract on PubMed.
||Chan-Yeung M, Evaluation of impairment/disability in patients with occupational
asthma. American Review of Respiratory Disease 1987
For more information or questions visit Michigan State
University's Occupational & Environmental Medicine Department, or contact them by phone at (517)353-1846