Home Sweat Specimen Collection as Part of Gravimetric Sweat Production Assessment for Axillary Hyperhidrosis Studies

pared (1) research site specimen collection and weighing, without transport, with (2) research site specimen collection and weighing, with transport by private vehicle or overnight courier.

Volunteers with primary axillary hyperhidrosis were invited to participate. Standard practices for collecting sweat by filter paper were followed.¹ Sweat production was measured for each axilla twice to yield four specimens per volunteer. Specimens were packaged in foam-lined cardboard shipping containers. Specimen assignment was random to one of the four different possible packaging and transport methods. Two specimens from each volunteer were packaged at ambient temperature and two were packaged with endothermic refrigeration packs, in order to maintain temperatures between 2-8^oC (Nanocool™ Albuquerque, NM). For each volunteer, one ambient and one refrigerated package was transported away and back to the research site by either private vehicle or overnight courier.

The specimens transported by private vehicle were driven around for 60 minutes. Interior vehicle temperature was maintained at approximately 72^oF. Upon return to the clinic, the specimens were unpacked and weighed. Time elapsed between collection and weighing of specimens transported by vehicle averaged four hours. The specimens transported by courier were shipped overnight from the research site. The daily high ambient temperature in the local area for those days ranged from 79 to 93^oF. Time elapsed between collection and weighing of specimens transported by courier averaged 24 hours.

Six volunteers participated yielding 24 sweat specimens. The average weight of sweat was 129.6 mg per specimen with a range from 6.8 mg to 546.4 mg. Table 1 illustrates values for tares, pre and post-transport total weights and sweat weights, and sweat weight change. Table 2 shows the percentage change in weight of sweat for each specimen, as well as grouped by method of transportation and packaging. The average absolute change in weight by percent varied from 1.05% to 5.45%. All but one of the refrigerated specimens gained weight during transport. This was thought due to condensation.

All methods demonstrated relatively low variability. However, ambient packaging and vehicle transport of specimens demonstrated the greatest consistency and least variance compared to standard office procedures. Although the collection and measurement of sweat during a research site visit remains the gold standard, remote specimen collection and transport under ambient temperature back to a research site for weighing appears to provide a reliable alternative when in-person visits are not possible.

The study and preparation of the research letter were supported by Brickell Biotech, Inc.
Stacy Smith was the study investigator and received payment from Brickell Biotech, Inc. Nancy Seretta, BS and Deepak Chadha, MS, MBA, RAC are employees of Brickell Biotech, Inc. Brandon Kirsch, MD is a former employee of Brickell Biotech, Inc. Dr. Kirsch is also a consultant to Brickell Biotech, Inc.

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2. Hund M, Kinkelin I, Naumann M, Hamm H. Definition of axillary hyperhidrosis by gravimetric assessment. Arch Dermatol 2002;138(4):539-541.
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Brandon Kirsch MD brandonmkirsch@gmail.com