Diagnosis can be achieved through a specialized form of electromyographic (EMG) testing called the long exercise test. This test measures the amplitude of a nerve response (called the Compound Muscle Action Potential or CMAP) for 40 to 50 minutes following a few minutes of exercise. In affected patients, there is a progressive fall in the amplitude of the potential. Besides the patient history or a report of serum potassium low normal or low during an attack, the long exercise test is the current standard for medical testing. Genetic diagnosis is often unreliable as only a few of the more common gene locations are tested, but even with more extensive testing 20–37% of people with a clinical diagnosis of<unk>  have no known mutation in the two known genes. Standard EMG testing cannot diagnose a patient unless they are in a full blown attack at the time of testing. Provoking an attack with exercise and diet then trying oral potassium can be diagnostic, but also dangerous as this form of PP has an alternate form known as hyperkalemic periodic paralysis. The symptoms are almost the same, but the treatment is different. The old glucose insulin challenge is dangerous and risky to the point of being life-threatening and should never be done when other options are so readily available. Factors known to trigger episodes are: stress, cold environment or hypothermia, carbohydrate load, infection, glucose infusion, metabolic alkalosis, alcohol, strenuous exercise, and steroids. People with<unk>  are often misdiagnosed as having a conversion disorder or hysterical paralysis since the weakness is muscle-based and doesn't correspond to nerve or spinal root distributions. The tendency of people with<unk>  to get paralyzed when epinephrine is released in "fight or flight" situations further adds to the temptation to misdiagnose the disorder as psychiatric.
Hypokalemic periodic paralysis
Sleep paralysis
Hyperkalemic periodic paralysis
Potassium-aggravated myotonia
Thyrotoxic periodic paralysis
Thyrotoxic myopathy
Alcoholic polyneuropathy
Glycine encephalopathy