HMW agent to which the patient had exposure were positive. The likelihood ratio calculation with a combination of tests showed that in a population with a 50% pretest probability a combination of positive test results adds to the posttest probability of sensitizer-induced OA.
In a study of suspected sensitizer-induced OA patients, the addition of induced sputum cell counts showing an increase in sputum eosinophils during periods at work compared to away from work improved the specificity of serial PEFRs by 18 to 26%, using SIC as the reference standard. Sensitivity was increased 8% with a cutoff level for increased sputum eosinophils of 1%, but was reduced with a cutoff level of 2%. This test is of no value, however, if the patient does not produce sputum during induction or cannot take time off from being in the suspected work area. Viagra Canada – see now.
For the exclusion of sensitizer-induced OA, a negative diagnostic test result, even a negative SIC response, is not always sufficient, and further diagnostic testing may be indicated (eg, serial PEFRs with or without methacholine testing or equivalent when on and off work). The results of different tests may not be concordant, since all tests have potential falsepositive and false-negative responses. The reasons include the following: intercurrent respiratory infections; medication changes; nonoccupational allergen exposures; variable exposures to the causative agent at work; and inadequate duration of time at work/off work to identify work-related changes in PEFRs. There can be a benefit from the repetition of such tests.
Most of the diagnostic tests providing objective evidence of work-relatedness are not relevant for those with suspected irritant-induced OA and are not included in the diagnostic criteria for that entity. They may be relevant, however, if it is suspected that the asthma-inducing exposure may also have caused sensitization (eg, from a spill of glutaraldehyde or diisocyanates).
WEA has been diagnosed most commonly by self-report of worsened asthma symptoms on the job in workers with preexisting asthma.