If it were me: You do the genetic test first. For her to have CF, she HAS to have that known mutation. However- If that comes back negative, you've ruled out CF and no other tests are needed, case closed AHHHHHH big sigh of relief. It's only a 50% chance that she did from whichever one of you carries it- way good enough odds to find out imo. <br>
<br>Should it come back positive- before treating her, you get her worked up at the cf center to see what her baseline is to figure out what seems reasonable. There are some tests that can be done that are not invasive at all that can give you some very good information- no doubt tests your other kids already get- but a seemingly 'healthy' kid can surprise you sometimes...
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<br>Start with the sweat test. It's non-invasive, inexpensive, quick, and usually not perceived as painful. Make sure they do both arms for best odds of success. However, keep in mind sweat tests are less than accurate at times, so... it's really hard to know how to proceed there. <br>
<br>Since her biggest symptom seems to be slowed growth, a 72-hour stool collection to test for fecal fat and elastase. Disgusting, yes- invasive, no. And will tell you with a good measure of certainty how her pancreas is doing. Along the lines of growth issues: labs for vitamin and mineral levels.
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<br>Sputum culture. If she comes back culturing anything, even stuff not exclusive to CF (staph, h.flu, etc) I'd want a chest xray done to look for early changes in the lungs often seen with CF.
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<br>If it was my child, I'd want to know all this before deciding how to proceed. Wait a minute, this WAS my child... hehehe. My son, now 14, has been deemed a symptomatic carrier- but we had to go through a lot of testing to be sure of that. Ultimately a non-cf result on a Nasal Potential Difference test tipped the scales over to the carrier side.