Cystic Fibrosis Sweat Test question?

My 16 month old is going in for a sweat test tomorrow to test for Cystic Fibrosis. Does anyone know what % of children around that age that go in for the test come out as positive for CF? Thanks for your help.

So my son went in today for the test. I was told by the nurse that they do 6 tests a day. About 5% of them are positive for CF. I'm anxiously awaiting the results. I'll keep you posted. Thanks.

sweat test may be ordered if a doctor thinks a child might have cystic fibrosis (CF). Cystic fibrosis is an inherited disease that causes sweat glands and other glands, especially those in the pancreas and the air passages of the lungs, to produce abnormally thick, clogging mucus. This clogging causes many problems for the patient, especially in the lungs. Though there are some promising new developments, there currently is no cure for CF, so early diagnosis and proper treatment are essential to improving the patient's quality of life and life span.

How Is a Sweat Test Done?
A device for collecting sweat is placed on the child's skin, and a colorless, odorless chemical is applied that causes the child to sweat. Assuming enough sweat is collected (sometimes collection can be difficult, especially in babies), the sweat is analyzed for sodium and chloride, components also found in blood, sweat, and tears.

The diagnosis of CF isn't made on the basis of just one test 鈥?it requires two (or more) abnormal sweat tests. When the level of chloride is elevated beyond a certain point in two consecutive tests, the child may be diagnosed with CF. However, a number of other conditions can also show elevated sweat electrolytes.

How Long Does a Sweat Test Take?
The sweat collection takes about 30 minutes to 1 hour. If not enough sweat is collected, the test may need to be repeated.

After a child is diagnosed with CF, further genetic testing can help doctors determine the specific type of the disease the child has

Cystic Fibrosis is the most common genetic disease of the white population; affecting 1 in 3300 births.
Please go to www.merck.com, go to the professionals choice, type in cystic fibrosis.
God bless.

While these are good answers, there is a more definitive test for cystic fibrosis. The sweat chloride is the old "tried and true" method, but the superior method would be a DNA test. The DNA test is specific for the mutation of the gene that causes cystic fibrosis. While the DNA test is more expensive, it is much more accurate and will tell you whether or not your child has CF.

Statistically, a child has a 1 in 4 chance of being born with CF, if BOTH parents carry the gene (you can carry the gene and not have CF). It takes the mutation from both parents to pass the disease on to the child.

In other words:
If mom does not pass on the gene and dad does not pass on the gene, the baby will not have CF.
If mom passes on the gene, but dad does not, baby will not have CF.
If dad passes on the gene, but mom does not, baby will not have CF.
If mom and dad pass on the gene, baby will have CF.

I hope this explains things a little for you. Good luck.

I like Barry M's answer about DNA testing. There are variations of the CF mutation that will not really show up in a sweat test.

As far as your question, Suean has given you the general distribution of CF births, but it's not really the answer to your question. I don't think you can get an exact answer, although you may not have meant exactly what you asked.

Only children who are suspected of having CF are sent for a sweat test. This means that a very large percent of those sent for the test will have a positive result. This figure would be meaningless to you, though. If your child is having a sweat test, CF must be at least suspected.

Go to http://www.cystic-l.com for the largest on-line support group and information center for Cystic Fibrosis.

Genetic testing is NOT more accurate since there are many genotypes that are not picked up. Especially among hispanics that have CF since the genes among this group is different than the Caucasion group. There are even Japanese cystics. Therefore, the sweat chloride is more accurate.

Having said that, it is a very technically difficult test and thus it is often goofed up. It should be performed only at a medical center that has a CF clinic/program. There are many university affiliated medical labs that mess it up.