In vitro diagnostic tests for immediate and delayed Drug Hypersensitivity Reactions
The diagnosis of drug allergy is currently not being correctly addressed and is overestimated, with confirmation in less than 40% of cases initially considered allergic. This diagnosis, correct or not, leads to the use of alternative antibiotics that can have more adverse effects and can induce bacterial resistance. Furthermore, this alternative is usually more expensive. Therefore, it is critical to perform an accurate diagnosis not only to improve patient safety but also to reduce public health expenditure.
The first approach to diagnose drug allergy is to complete a detailed questionnaire and clinical history, which are often very difficult to retrieve. After that, the initial choice is to perform a skin test and, if negative, a drug provocation test where an increasing dose of the drug is administered until the dosage is complete or an allergic reaction occurs. Both skin testing and drug provocation tests are not exempt of risk for patients, are time consuming and add an important cost to the healthcare system.
Therefore a more rational alternative for diagnosis could consist of laboratory tests also denominated as in-vitro tests. However, tests with sufficient sensitivity for diagnosing are currently not available and results also depend on the type of reaction and the drug involved.
It is a priority to investigate this area as an improvement in accuracy would have positive impact on the quality of life of patients.