A medical assistant is performing a scratch allergy test on a patient's back. Which of the following distances describes the correct spacing for the small amounts of allergen scratched onto the skin?

In performing a scratch allergy test, it is important to space the allergens appropriately to avoid overlapping responses that could create ambiguity in the results. The correct spacing of 1 to 1 1/2 inches allows for sufficient distance between each scratch to minimize the risk of cross-contamination and ensure that each reaction can be accurately assessed.

This spacing is optimal because it provides enough room for potential skin reactions to develop while still fitting the allergens onto the testing area of the back. If the allergens were spaced too far apart, it could lead to wasted space on the skin where reactions might not be measurable, complicating the interpretation of results. Conversely, spacing them too closely could result in overlapping reactions, making it difficult to determine which allergen caused a response.

Each of the incorrect options suggests either too far apart or too close together, which would not be suitable for obtaining clear and interpretable results from the allergy test. Adjusting the distances ensures that the test is effective and that accurate information can be gathered to guide patient management.