Concerned over diagnosis

[6FT2]

Hi,

I have Marfan's syndrome but was having more problems with my joints than the usual patient so my doctor did blood tests for RA and various other related issues.  They didn't find any problems with my joints so that is more than likely all down to wear and tear but instead, they found that I have very high enzyme levels relating to the mucus/sweat gene.

Is the enzyme test sufficient to make an accurate diagnosis of Cystic Fibrosis or should I insist on a sweat test...  I don't like asking a doctor for further tests, as I would assume they would request it if necissary and tend to get upset thinking that you are questioning their abilities but I have found that some doctors tend to close the book after the first positive test result while others insist that, for example with the MFS dx that I should have had further tests done.

Althoug I understand that MFS especially, is very difficult to pin down and that not even gene tests is always accurate, but it is quite frustrating.

If you have any advice, I would be very appreciative.

Could you also explain to me what the difference is between a Diagnosis and a Clinical Diagnosis?

Thanks in advance

Andre T. Dreyer

[Jordanna Joaquina, MS, CGC]

There are different methods used to diagnose cystic fibrosis.

- A chloride sweat test is one of the methods used to diagnose cystic fibrosis. A small electrode is placed on the skin to stimulate sweat production. The amount of chloride (a component of salt in the sweat) is then measured. A chloride concentration greater than 60 mEq/L in sweat on two separate occasions is diagnostic of CF.

- Nasal transepithelial potential difference (NTPD or NPD) testing can be used to assess the function of the cystic fibrosis gene product, a chloride channel called cystic fibrosis transmembrane conductance regulator (CFTR). Certain measurements are characteristic of CF.

- Clinical genetic testing for CF looks for mutations in the CFTR gene that cause the condition. CF is an autosomal recessive condition and as such, it is generally necessary to have two mutations, one in each gene copy, to be affected with the disorder.

We recommend that you meet with a medical geneticist for evaluation and to discuss your symptoms, Marfan syndrome as well as the benefits and limitations of genetic testing. You can find a medical geneticist at the American College of Medical Genetics website. We wish you the best.

[6FT2]

Hi Elaine,

Thank you for the information.

They identified the elevated enzyme level through a blood test.  Is this the test you were talking about or is there another test?

Thanks

Andre