Sweat test

Revision as of 19:32, 22 February 2010 by Apalmer (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search

WikiDoc Resources for Sweat test

Articles

Most recent articles on Sweat test

Most cited articles on Sweat test

Review articles on Sweat test

Articles on Sweat test in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Sweat test

Images of Sweat test

Photos of Sweat test

Podcasts & MP3s on Sweat test

Videos on Sweat test

Evidence Based Medicine

Cochrane Collaboration on Sweat test

Bandolier on Sweat test

TRIP on Sweat test

Clinical Trials

Ongoing Trials on Sweat test at Clinical Trials.gov

Trial results on Sweat test

Clinical Trials on Sweat test at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Sweat test

NICE Guidance on Sweat test

NHS PRODIGY Guidance

FDA on Sweat test

CDC on Sweat test

Books

Books on Sweat test

News

Sweat test in the news

Be alerted to news on Sweat test

News trends on Sweat test

Commentary

Blogs on Sweat test

Definitions

Definitions of Sweat test

Patient Resources / Community

Patient resources on Sweat test

Discussion groups on Sweat test

Patient Handouts on Sweat test

Directions to Hospitals Treating Sweat test

Risk calculators and risk factors for Sweat test

Healthcare Provider Resources

Symptoms of Sweat test

Causes & Risk Factors for Sweat test

Diagnostic studies for Sweat test

Treatment of Sweat test

Continuing Medical Education (CME)

CME Programs on Sweat test

International

Sweat test en Espanol

Sweat test en Francais

Business

Sweat test in the Marketplace

Patents on Sweat test

Experimental / Informatics

List of terms related to Sweat test

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [2] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

Overview

The Sweat test measures the concentration of chloride and sodium that is excreted in sweat. It is used to diagnose cystic fibrosis (CF).

Method

Sweating is induced by pilocarpine iontophoresis. At the test site, an electrode is placed over gauze containing pilocarpine and electrolyte solution that will not interfere with the sodium and chloride measurement. A second electrode (without pilocarpine) will be placed at another site and a mild electrical current will draw the pilocarpine into the skin where it stimulates the sweat glands.

The test site is carefully cleaned and dried, then a piece of preweighed filter paper is placed over the test site and covered with paraffin to prevent evaporation. Specialized collection devices may also be used. Sweat is collected for 30 minutes. The filter paper is retrieved and weighed to determine the weight of sweat collected. Several laboratory methods are then used to determine the sodium and chloride concentrations.

Results

Reference ranges

If the concentration of chloride is >60 mEq/L, the test is positive; 40-60 mEq/L is borderline; <40 mEq/L is negative. The reference range for sodium is <70-90 mEq/L. The minimum sample weight varies with the collection method.

Interpretation

Two reliable positive results on two separate days is diagnostic for CF. Because of the existence of milder variants, borderline or even near-borderline negative results may be used to diagnose CF. Clinical presentation, family history and patient age must be considered to interpret the results. Highly discordant sodium and chloride values may indicate technical errors.

Sources of Error

Technical errors, insufficient sample, evaporation, contamination, dehydration, mineralocorticoid hormone therapy, and skin rash on the tested area may produce incorrect results. False positive test results may be caused by malnutrition, adrenal insufficiency, glycogen storage diseases, hypothyroidism, hypoparathyroidism, nephrogenic diabetes insipidus, G6PD deficiency or ectodermal dysplasia (source: http://www.eMRCP.com)

External links

nn:Sveittetest