To diagnose botulism, a physician will begin by performing a complete physical examination and compile a thorough medical history of the patient. A physician may also inquire about the patient’s recent eating patterns, any recent wounds or other information that might suggest botulism.

Certain blood tests or stool tests are necessary to definitively diagnose botulism. These tests involve taking samples of a patient’s blood or stool for laboratory analysis. This testing is necessary because the symptoms of botulism may also indicate other illnesses, including certain neurological disorders (e.g., Guillain-Barré syndrome, stroke, myasthenia gravis).

If other disorders are suspected, additional tests may be performed. These tests may include brain scans, spinal fluid examination (spinal tap), nerve conduction velocity tests, electromyography and a Tensilon test (used to diagnose myasthenia gravis).