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Health and medicine
Cystic fibrosis diagnosis
Created by Amy Fan.
Want to join the conversation?
- Because the test is based off of sweat chloride, is the diagnosis easily accessible to impoverished and third world countries?(4 votes)
- A lot of things that seem cheap or easy are still difficult to find in resource poor environments. Couple this with the low incidence of CF in the majority of these countries, I'd be surprised if it were readily available outside of a major city/central pediatric hospital.(6 votes)
- Thank you for the wonderful video. i'm just wondering if they do sweat test as a newborn screening in US? From what I understand, we do Heel prick test as CF screening and only do sweat test as diagnostic tool if the screening is positive. I just want to clarify if i'm understanding your explanation wrongly or if it's the case in US?(1 vote)
- athe this particular type of pneumonia, what types are there 3:08(1 vote)
- we did this thing called 'cents for CF, and we collected money for research and other things with CF. My former teacher knows a girl with CF. She's barely at school!(1 vote)
- What are the symptoms in CF??(0 votes)
- You can watch the Complications video or the What Is video(1 vote)
- Do the Cl- ions get trapped in the lung or They can not get out?(0 votes)
Video transcript
- [Voiceover] The gold
standard for diagnosing Cystic Fibrosis is called the Sweat Test. Now it's not where you have to exercise a lot and sweat a lot,
but the sweat is used to analyze how much chloride is in there. So the point of this whole
test is how much chloride. And an abnormally high chloride
points to Cystic Fibrosis. A lot of times this test is done in babies and for full-term babies
actually age two to four weeks you can already have an accurate test. And the reason why they might get one or the doctor might
order one is for example, if they have a genetic
reason to maybe have CF, their parents carry the gene or they could have an
abnormal newborn screen. Now every baby who is born in the hospital gets a newborn screen. They test for metabolic
factors, things that can potentially point to CF
and if they have something abnormal there they
usually get the Sweat Test. So it's a test that we
do if we suspect CF. And the way it's done
is actually very simple. The baby or the person doesn't
really even have to move. So first we apply a solution to the skin, wherever the area we're testing, which encourages it to make sweat. And then we take two electrodes,
one positive, one negative, put it on the skin, turn on the current and this current stimulates
the sweat glands. So if this is the skin, back
here is the sweat gland. So after it is stimulated to
make sweat we then collect it, send it to the lab and see
how much chloride there is. That is the Sweat Test. Of course you can always
go for genetic testing, right to the source of the gene. We already know what the gene
is, and remember it's CFTCR. A thing to remember about
this is that even though this is the gene that causes the disease there are many variations
between people who have CF who have different variants of it, so it's not always as cut and dry, but for the most part analyzing this gene, seeing if it's normal can diagnose the CF. The Sweat Test and genetic testing are more or less answering
a yes or no question, but to ask that question
at the appropriate time there are diagnostic clues
that we should look for in people who might not
know that they have CF. So for people who work
with kids when they're even just babies it's
important to watch out for people who have failure to thrive, which just means they're not gaining weight and growing as they should. And the first thing you do is make sure the parents are feeding them correctly. But after that you start looking for what we call organic causes, or what's within the baby's metabolism that causes this, and CF is a big one. So failure to thrive, maybe
it's good to do a Sweat Test. Or people who are having a lot
of frequent, long infections, especially with bacteria
or organisms that are not usually found in normal people. For example psuedomonas, this
is something that thrives in the environment of the thick mucus that Cystic Fibrosis patients
have in their lungs. So this is a type of
pneumonia that's seen in a lot of CF patients, but not
necessarily in people who don't have it, so this again should tip you off to look for the CF. Of course there's malnourishment,
malnutrition I should say because they can eat all
the food in the world, but if CF stops their
pancreas from helping them digest it then they
will have malnutrition. You can get things like
a chest x-ray if you want to see the overinflated lungs. You can get abdominal x-ray in babies because CF can affect the intestines and sometimes it is visible on the film. But one thing, actually
speaking of babies, that I want to point
out is to watch out for babies who have delayed meconium. Not to gross you out,
but meconium is the brown sludge that comes out of a
baby when they're first born. It's kind of like their first
poop, but it's not real poop because they haven't eaten
yet, but if the sludge doesn't come out there are
several reasons that could be and CF is one of the major reasons. So working with newborns
if they don't pass meconium within the first
few hours like normal babies do, it's worth it
to look into that further and see if they possibly
could have Cystic Fibrosis. Diagnosing CF is not really a huge mystery because we know the gene,
we know the Sweat Test has a good accuracy, so
the key in Cystic Fibrosis diagnosis is to watch out for these clues and think of CF when you see them.