Calls to standardise allergy tests to improve reliability

Scientists are calling for standardisation of allergy tests after laboratory trials showed commercially available tests are not uniformly reliable.

Some of the preferred skin prick test extracts lacked the sufficient amount and diversity of important shellfish allergens, meaning test results could be falsely negative, putting lives at risk, according to a new study led by Dr Thimo Ruethers from James Cook University’s Australian Institute of Tropical Health and Medicine (AITHM) and JCU’s Tropical Futures Institute (TFI) in Singapore.

In Australia, shellfish allergy affects up to 3% of the general population — it is usually lifelong and commonly triggers anaphylaxis, a condition that leads to respiratory collapse and can be fatal, Ruethers said.

“Skin prick testing (SPT) is often the preferred first-line diagnostic approach. This involves a health worker placing a drop of allergen extract on the surface of the arm then pricking through it into the arm. If you are allergic to the allergen you will have a small, itchy swelling and a reddening of the skin after 10–15 minutes,” said Professor Dianne Campbell from The Children’s Hospital at Westmead, Sydney.

But Ruethers warned that widely used allergen extracts in commercial SPT kits are generally not standardised, limiting the diagnostic value of results.

“In 2019, we demonstrated considerable variability in effectiveness for 27 commercial SPT extracts for fish allergy.

“In the current study, using biochemical and immunological methods and mass spectrometry, we tested 11 commercial crustacean and five mollusc SPT extracts and found even greater critical variability in their reliability,” said JCU’s group leader Professor Andreas Lopata.

“Standardisation of allergen extracts is urgently needed to improve the accuracy and reliability of SPTs,” Ruethers said.

“Also, improvements in blood tests, along with the development of region-specific allergen extracts with known quantities of clinically well-characterised allergen components, are critical to achieve considerable improvements in allergy testing.”

Ruethers said developing more reliable allergy diagnostics requires further interdisciplinary research and is urgently needed to safeguard allergy sufferers globally. He said food allergies pose major public health concerns, lower the quality of life and can be fatal.

Image credit: iStockphoto.com/AlexRaths