Staff at the helpline have at least four years experience as registered nurses, and regularly complete training in critical thinking and clinical reasoning.
The nurse in question, who is currently not working, is believed to have five years experience.
Only doctors are allowed to diagnose patients who call the helpline, with staff given strict guidelines on how to respond to callers.
While the service is not an emergency service and doesn't replace medical consultation, it connects Queensland residents to registered nurses who can assess patients' symptoms and provide health information.
It also provides referral to other healthcare providers, and guides callers to the appropriate level and location of care, with nurses estimating "symptom urgency, rather than diagnose the cause of the symptoms".
An investigation into the incident is underway.