The Minor test (also known as Minor's test, the starch–iodine test, and the iodine–starch test), described by Victor Minor in 1928, is a qualitative
medical test
A medical test is a medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic ...
that is used to evaluate
sudomotor
Sudomotor function refers to the autonomic nervous system control of sweat gland activity in response to various environmental and individual factors. Sweat production is a vital thermoregulatory mechanism used by the body to prevent heat-related ...
function (
perspiration
Perspiration, also known as sweat, is the fluid secreted by sweat glands in the skin of mammals.
Two types of sweat glands can be found in humans: eccrine glands and Apocrine sweat gland, apocrine glands. The eccrine sweat glands are distribu ...
or sweating).
Method
Tincture of iodine
Tincture of iodine, iodine tincture, or weak iodine solution is an antiseptic. It is usually 2% elemental iodine, along with potassium iodide or sodium iodide, dissolved in a mixture of ethanol and water. Tincture solutions are characterized by ...
is applied to the skin and allowed to air-dry. After drying, the area is dusted with
cornstarch
Cornflour, cornstarch, maize starch, or corn starch (American English) is the starch derived from corn (maize) grain. The starch is obtained from the endosperm of the kernel. Corn starch is a common food ingredient, often used to thicken s ...
or
potato flour
Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many cultures ...
. Sweating is then encouraged by increased room temperature, exercise, use of a sauna, or
pilocarpine
Pilocarpine, sold under the brand name Pilopine HS among others, is a lactone alkaloid originally extracted from plants of the Pilocarpus genus. It is used as a medication to reduce pressure inside the eye and treat dry mouth. As an eye drop ...
.
When sweat reaches the surface of the skin, the starch and iodine combine, causing a
drastic color change (yellow to dark blue), allowing sweat production to be easily seen.
Some have reported higher sensitivity and fewer drawbacks marking dry skin with water-erasable ink and observing fading.
Uses
The Minor test can be used as a diagnostic tool to evaluate underactive (
hypohidrosis
Hypohidrosis is a medical condition in which a person exhibits diminished sweating in response to appropriate stimuli. In contrast with hyperhidrosis, which is a socially troubling yet often benign condition, the consequences of untreated hypohidr ...
)
and overactive (
hyperhidrosis
Hyperhidrosis is a medical condition in which a person exhibits excessive perspiration, sweating, more than is required for the Thermoregulation, regulation of body temperature. Although it is primarily a physical burden, hyperhidrosis can deterio ...
) sweating. This test can also reveal
Horner's syndrome
Horner's syndrome, also known as oculosympathetic paresis, is a combination of symptoms that arises when a group of nerves known as the sympathetic trunk is damaged. The signs and symptoms occur on the same side (ipsilateral) as it is a lesion ...
.
References
Notes
*
*{{MedlinePlusEncyclopedia, 007259, Hyperhidrosis (excessive sweating)
Medical tests