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CAP Certified Sweat Test Lab, Torre Medica Auxilio Mutuo Suite 215, San Juan, PR
What does the sweat test tell us?
Your doctor has asked that this test be performed to rule out the presence of CF, an inherited disorder of the lungs, intestines and sweat glands. Symptoms include cough or wheezing, repeated episodes of pneumonia, chronic diarrhea and difficult gaining weight. Individuals with CF have an increased amount of sodium and chloride (salt) in their sweat in addition to one or more of the symptoms described above,
In general, sweat chloride concentrations less than 40 mmol/L are normal (does not have CF); values between 40 to 60 mmol/L are borderline, and sweat chloride concentrations greater than 60 mmol/L are consistent with the diagnosis of CF. For infants less than 6 months old a sweat chloride concentration > 30 mmol/L needs further evaluation. For individuals who have CF, the sweat chloride test will be positive from birth and can be done after 2 daysold. Once a test result is positive, it is always positive. Sweat test values do not change from positive to negative or negative to positive, as a person grows older. Sweat test values also do not vary when individuals have colds or other temporary illnesses. The symptoms described above are commonly seen in a number of childhood illnesses other than CF. We perform many sweat tests each year, and only a very small number are positive thereby diagnosing CF. In most cases, the results of the sweat test rule out the possibility of CF.
Experience to date
Our sweat testing facility is the only CAP certified facility in Puerto Rico to perform sweat testing and has more than 25 years performing this specialized testing.
We are the referral center for sweat testing who serve many pediatric and adult specialists including the Newborn Screening Program of Puerto Rico.
We are the only facility in Puerto Rico performing the gold standard chloride quantitative sweat chloride measure using the confirmatory Gibson and Cook method as recommended by the Cystic Fibrosis Foundation Guidelines. (Cystic Fibrosis Foundation Center Committee. Sweat Testing Standards Memorandum, December 2006, Bethesda, Maryland.)
Other Test Performed for Diagnosis of Cystic Fibrosis
Prenatal screening and Newborn screening for CF are performed in Puerto Rico and in case of a positive test, it must be confirmed by the sweat test method performed in our Lab which is the "gold standard" for diagnosis of CF. Other methods for sweat testing (i.e. Wescor-Sweat-Check) are recommended only for screening purposes and any positive result should have a confirmation test such as the one performed in our Lab.
There are more than 1000 mutations detected in CF cases. We have tested most of our CF cases and in our Lab we offer service for the genetic analysis of CFTR mutations for CF. Hispanics had shown different mutations seen in other ethnic groups. However, because there are so many described mutations some patients with clinical features of CF may have only one or no CFTR gene mutations identified by mutation analysis. For these individuals, additional testing and evaluation should be done in a specialized CF clinic.