Two complementary investigations
A skin prick test investigates an immediate skin response to an allergen extract. Specific IgE is a blood test for antibodies directed against a particular allergen. Both can provide evidence of sensitisation, but they are not interchangeable for every substance. The clinician selects an investigation based on symptoms and the suspected exposure rather than requesting an unspecified allergy screen.
Where they can help
At work, these tests may support investigation of allergy to proteins in flour, enzymes, laboratory animals or natural rubber latex. The availability and quality of extracts vary. The tested allergen must correspond to the suspected material: a result for a different protein does not answer the same occupational question. Useful validated tests are unavailable for many chemical agents. A broad panel requested without understanding workplace materials can generate findings that do not answer the actual question about a task or product.
Sensitisation is not the whole diagnosis
A positive result indicates immune recognition of an allergen, but must be assessed against compatible symptoms and actual exposure. It does not measure the airborne concentration or predict the severity of a future reaction. Raised total IgE does not identify a particular agent. Assessment of respiratory sensitisation therefore requires both clinical and workplace information.
Reconstructing the exposure history
Record tasks, products, ingredients, symptom timing and changes during periods away from exposure. Rhinitis, eye irritation and breathing symptoms can provide clues, but do not establish causation on their own. When asthma is suspected, the clinical team may need lung function testing and further investigations in addition to allergy tests. The different findings must be interpreted together.
Why negative results occur
A negative result does not exclude every occupational allergy: the relevant extract may be unavailable, another mechanism may be involved or test sensitivity may be limited. Some medicines and skin conditions influence skin testing. Preparation is determined by the specialist. Employers should neither recommend stopping treatment nor arrange deliberate workplace exposure to see whether symptoms can be reproduced.
Using the findings for prevention
A result should inform a practical decision: identify a source, reduce exposure or assess an alternative suitable for the sensitised person. It does not replace risk assessment for other workers. Testing requires clinical supervision and appropriate facilities for adverse reactions. Occupational health communicates necessary workplace adjustments through the proper process while keeping individual clinical results confidential and following up any continuing symptoms.
