What should be the first action of a school nurse when a child with type I diabetes reports weakness after an insulin injection?

In the scenario where a child with type I diabetes reports weakness following an insulin injection, the first action of the school nurse should be to measure the blood sugar. This step is critical as it provides immediate information regarding the child's current blood glucose levels, allowing the nurse to determine whether the weakness is a result of hypoglycemia (low blood sugar) or another issue.

By measuring blood sugar first, the nurse can make an informed decision about subsequent actions, such as administering glucose or carbohydrates if hypoglycemia is confirmed. This approach prioritizes safety and accuracy in managing the child's diabetes, ensuring that the appropriate treatment is provided based on the specific situation.

The other options, while related to diabetes management, come after confirming the blood sugar level. Administering glucose without checking could lead to unnecessary treatment if the blood sugar is not low. Calling the parents is important but should follow immediate assessment and care. Providing carbohydrates also depends on knowing the blood sugar level to ensure it is necessary and safe.