If the sweat test is being done just as a precaution and you aren't seeing anything of concern that warrants a test right this second- to be honest, it might be more accurate if done when she is a little older. Sweat tests on very young babies aren't always as accurate as they would be once they are a little older.
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<br />The sweat test itself:
<br />Areas of skin on each arm (may be leg on a young baby) will be cleaned and then two discs are applied to the skin on each limb. One disc on each limb will have pilocarpine gel applied to it, which when in contact with your baby's skin, will stimulate sweating. The discs are attached to the skin with velcro straps. Once attached, a mild current is activated for about 10min or so to stimulate absorption of the pilocarpine gel into the skin. This is not supposed to be painful- one of my sons told me it feels warm, one told me it feels tingly, both told me it didn't hurt. My daughter, who has severe sensory issues, simply told me it was warm, with no other complaints other than not wanting to stay in the chair. <img src="i/expressions/face-icon-small-wink.gif" border="0"> Once this part is done, the electrode discs come off. The skin will be bright red as if it was burned but this fades and didn't seem to be painful to any of the kids. I mention it so you'll be prepared for what it looks like. A sweat collector that looks like a wristwatch will be strapped on over the area that had the pilocarpine gel applied to it. You'll see the 'coil' on the face of it, which will turn color as it fills with sweat. This will take anywhere from 10-30min. There is a time limit for how long it can take for enough sweat to be collected; it's got to be within 1/2hr or so. Bringing extra clothes to dress the baby extra warmly if needed is a good idea, i found a hallway to let my kids run up and down the hall in their winter coats (it was winter for us anyway) but obviously with a baby warm clothes is all you can do. Once the collector comes off, it's done. <img src="i/expressions/face-icon-small-smile.gif" border="0"> Results are in fast: within a day or two. Emily had hers done in the morning and I got a call late that afternoon. When her repeat test was done in the afternoon, I got a call the next day.
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<br />My other thought on this situation: are you noticing that she tastes a bit salty or anything of concern when you change her? Very frequent or greasy stools or anything else? If anything of concern is present, a normal sweat test really won't be enough to rule CF out- esp if she has a rare 2nd mutation. Some of them are specifically associated with lower sweat test values. If there's anything of even slight concern that has you worried at all, I'd try to get an Ambry test for her- it's so simple to do, a single vial of blood- and then you can lay it to rest with a much higher degree of certainty. Getting the baby's dr to help however needed so insurance will cover it would be so worth it to gain you peace of mind now and not go through endless 'is it or isn't it' for months and years to come as others have gone through. <img src="i/expressions/face-icon-small-smile.gif" border="0">
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<br />Wishing the very best. <img src="i/expressions/face-icon-small-smile.gif" border="0">
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