What is the quantitative sudomotor axon reflex test (QSART)?

The quantitative sudomotor axon reflex test (QSART, or sweat test) measures the nerves that control sweating. The test can help diagnose autonomic nervous system disorders, peripheral neuropathies and some types of pain disorders. The autonomic nervous system controls the working of your body’s internal organs, which includes regulating body temperature, blood pressure, heart rate and digestion.

The test involves a mild electrical stimulation on the skin called iontophoresis, which allows acetylcholine, a naturally occurring chemical, to stimulate your sweat glands. The QSART measures the volume of sweat produced by this stimulation.

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