5 Weird Things Your Blood Can Tell You


This episode of SciShow is sponsored by Brilliant! Go to Brilliant.org/SciShow to learn more. [♪ INTRO] It usually isn’t possible to simply glance
at a sick person and instantly know exactly what disease they
have. In order to diagnose diseases and assess risks,
doctors often rely on biomarkers, a broad category that basically represents
anything they can measure to learn something about your health. And one of the easiest things to collect and
measure is blood. But blood is fairly exceptional, in that it
doesn’t only tell you about blood-related diseases. It can reveal information about everything
from your brain to your unborn fetus. Here are five things your blood can tell you
about your health that you might not expect. Doctors are working on ways to predict if
your baby will be born up to two months prematurely based on patterns
in your blood. Premature birth is one of the leading causes
of infant death worldwide. Around 15 million babies are born before 37
weeks every year. But one way to help this at-risk population
is by knowing their gestational age: exactly how long they’ve been developing
in the womb. While being born prematurely carries risks
no matter what, the chance of medical complications increases
as gestational age decreases. So if a baby is born prematurely, a solid
idea of how developed it is will help doctors prepare for those complications. Technologies like ultrasound can help us find
gestational age, but they don’t give us as much information
as we’d like on how likely a baby is to be born early. Recently, scientists have turned to things called
cell-free RNA transcripts, or cfRNA for short. These are bits of the fetus’s genetic information
that make their way into the parent’s blood. Different genes are expressed at different
times during pregnancy, so depending on the amount of cfRNA we find
from different types of tissue, we can get an idea of the fetus’s gestational
age and risk for premature birth. One 2018 study attempted to determine the
genetic patterns in more detail, in order to develop a cfRNA-based blood test
to estimate the risk of preterm birth. They saw some things they expected, like increased cfRNA from the placenta and
liver as the fetus developed. Then they used those patterns to make a model
and estimate when the baby would be born. While the resulting model was fairly accurate
at measuring gestational age, it didn’t do any better than ultrasound. And it could only accurately predict the delivery
date for full term births, not preemies. A few different things can trigger a preterm
birth, and since we don’t totally understand how
they work yet, the research group thinks those unknown factors
might be why their estimate isn’t super accurate. This new blood test isn’t quite ready for
the clinic yet. The first experiment only tested a small number of white and African American people at risk
of preterm birth. In the future, larger and more diverse samples may be able to help develop a truly usable
blood test. Hitting your head is serious. And if you hit your noggin just right, you
might experience memory loss, dizziness, or other mental alterations, all of which are signs of a traumatic brain
injury called a concussion. But no two concussions are diagnosed the same,
so doctors need some objective markers. Recently, they’ve used a blood test in combination
with imaging like CT scans to help them diagnose head injuries. When someone presents with signs of a concussion,
doctors first give them a blood test, and they’re looking for two biomarkers in
particular, GFAP and UCH-L1. They’re great biomarkers for head injuries
because the amount we can detect increases with the severity of the injury,
so how much there is tells us how bad it is. Plus, GFAP is only expressed in the brain, which makes it a very specific marker for
head trauma. So that’s great for concussions. But if someone hits their head and doesn’t
show concussion symptoms, we’d still like to know how bad their injury
is. Repeated smaller head injuries can still carry
long term health risks, like for athletes who experience repeated
minor head trauma. So doctors need a way to track these milder
injuries. A study published in 2019 looked at GFAP and
UCH-L1 in people with head injuries. Participants were categorized as either having
concussion symptoms, head injury without symptoms, or body trauma
only. The researchers tracked these biomarkers at
different times after the injuries to see if any patterns emerged. They found that both biomarkers were elevated
after head trauma, although the level of UCH-L1 in someone’s
blood was higher after even minor head injuries, meaning it wasn’t useful for showing how
bad the injury was. GFAP, on the other hand, scaled up more consistently
with the severity of head trauma, even when the person didn’t show symptoms. This means that while both are still good
markers for diagnosing concussion, GFAP was more informative when it came to
showing how bad. While many doctors’ offices already test
for these biomarkers, the researchers say that a wider range of
measurement devices, like for ambulances, may be available very
soon. By now you probably know that heart disease
is kind of a big deal. Heart disease is still the biggest killer
in the world, and having narrowed or blocked coronary arteries,
otherwise known as atherosclerosis, is one of the many risk factors for that. But as you can imagine, no single test predicts
your risk for this disease perfectly. For instance, we already have plenty of biomarkers
for cardiovascular disease risk by itself. But if you have narrowed arteries, some of
those biomarkers all of a sudden aren’t as accurate. There are a few ways to measure how blocked
those vessels are, though. This includes stuff like echocardiograms and
exercise. In early 2019, research out of Duke University
Medical Center tried to develop a test that used both exercise
tests and biomarkers. Using a combination of tests would give them
a better idea of what happens chemically around ischemia,
when the heart doesn’t get enough oxygen. Specifically, they wanted to see what happened
to those biomarkers over the course of an exercise test and pick
out any interesting patterns. The researchers were interested in about 60
chemicals related to the heart’s energy usage. In particular, a group of chemicals called
acylcarnitines. So they recruited participants who were already
patients in the emergency department with heart disease symptoms like chest, jaw
or shoulder pain. Researchers took blood samples before and
after the exercise test and did an echocardiogram to get a picture
of how blocked their coronary arteries were. Their results narrowed it down to four acylcarnitines
and one amino acid that might be good at predicting atherosclerosis
in the future, and identified which ones change after exercise. The researchers claim their method is a better
predictor of atherosclerosis than the blood tests we have now, since it gives a
snapshot of conditions before and after ischemia. The catch is, we don’t yet know how much
better. It’s still too early to say when this will
be used more regularly. A study with a larger sample size is still
needed to validate these initial findings. It may seem strange that a chemical in your blood could be used to diagnose a mental health
condition, but it’s totally a thing. For how widespread depression is, we still
don’t really understand the physiology behind it. Having some kind of biomarker for depression
would allow doctors to come up with more consistent diagnoses
and more targeted treatments. But what chemical are we looking for? Recently, a chemical called acetyl-L-carnitine,
or LAC for short, has been getting some attention thanks to
its antidepressant action in rodent studies. LAC is involved in a chemical pathway that
ultimately regulates the release of a neurotransmitter
called glutamate, one of the chemicals that neurons use to communicate
with each other. Now, as far as we can tell in animal models,
adding LAC to their diet can work as an antidepressant if that animal
had a low level of LAC to start with. But that doesn’t necessarily mean it works
in people, so researchers have started looking into that, too. In a 2018 study, researchers recruited over
100 participants from two different medical centers, gave them all clinical psychiatric exams,
and drew some blood. On average, participants with diagnosed depression had lower LAC concentrations than the control
group. And among those participants with moderate
to severe depression, things like childhood trauma and a younger
age of onset were associated with even lower LAC levels. The research so far only supports LAC for
diagnosing depression, not as an oral supplement to treat it. Although that hasn’t stopped companies from
trying to sell it for that purpose. However, researchers were optimistic that
with more clinical validation, patients with depression and low LAC might
one day benefit from LAC supplements. But it won’t ever be a one size fits all
mood boosting pill. Alcohol use disorder, or AUD, is a potentially
life-threatening condition, and detecting it is trickier than it seems. There are different types of drinking behavior
associated with AUD. Binge drinking in particular is especially
common on college campuses. But researchers aren’t gonna follow college
students to the bars on Saturday nights, so they gather data by having their participants
fill out questionnaires. All of these questionnaires ultimately try
to get information about how much and how often these folks are drinking. One of them, the Alcohol Use Disorders Identification
Test, or AUDIT, is the best at actually identifying binge
drinking in college students. But questionnaires are still subjective. And using a concrete number, like a measurable
biomarker, would allow for more objectivity in screening
for AUD and getting help for those who need it. We already have urine tests to see if someone
abstains from alcohol, but no tests that define alcohol use disorder. One of the best candidates for an AUD test
is a biomarker called phosphatidylethanol, or PEth, a molecule that only shows up in the blood
when alcohol is present. But finding a little bit of PEth in someone’s
blood doesn’t diagnose AUD, and a single alcoholic beverage doesn’t
raise PEth levels any noticable amount. Unfortunately, because each study that measures
PEth and alcohol use has been designed differently, it’s hard to compare them side by side and
come up with a definitive range of PEth levels. The only thing we can really say is that the
more you’ve been drinking lately, the higher your PEth. So a study published in 2015 tried to double
up the diagnostic power and tested the AUDIT questionnaire with PEth
levels in the blood. To do this, they recruited young adults from
college campuses and had them complete the AUDIT to learn about
their alcohol consumption behaviors. The questionnaires put them into one of three
groups: binge drinkers, moderate drinkers, and abstainers. Like in past studies, the researchers found
more PEth in the blood of binge drinkers than moderate drinkers and none in the abstainer
group. That makes PEth an extremely sensitive and
objective measure for alcohol consumption. But again: details. What that really tells us is that PEth is
associated with how much alcohol someone drinks, not how often, what time of day, or their
relationship with alcohol. In other words, there’s a bunch of variables
that it can’t pin down. This study still depended on self-reported
questionnaires, so it isn’t enough evidence to say that
PEth levels can identify if someone has AUD. With all of these biomarkers, it’s important
to remember that they’re adding to the pool of information that healthcare
professionals use during treatments. One marker isn’t necessarily the end-all,
be-all test for diagnosing a condition. But with more in-depth research into each
of these chemicals, doctors get a more precise picture of their
patients’ status. And that information can be used to help improve
their outcomes. Thanks for watching this episode of SciShow,
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100 thoughts on “5 Weird Things Your Blood Can Tell You

  1. Huge thanks for saying "Here is 5 things your blood can tell about you that you MIGHT not expect" instead of saying "5 THINGS YOU NEVER KNEW or MUST KNOW ABOUT….". Being really sincere, here. I really, truly appreciate this way of handling information. Really bothered when a video (even on the information is legit) tells me "what i dont know" or "what i should no", etc.. Thanks for being awesome, SciShow

  2. Can't say the word, "mother"? As a biological male who is a parent, are you saying that a blood test from me can show biomarkers for premature birth?

  3. I donated but I understood it was basically just a gesture. Lets be honest, a world with an extra 20 million trees is better than a world without 20 million trees.

  4. I'll bet there's even MORE weird things our blood could tell us (things like: "That dress DOES makes you look fat!" or "Fyi, tomorrow isn't ANYONE's birthday!" , etc), but how do we know our blood isn't just messing with us?

  5. My blood had white blood cell poison
    Ask #nhs what in radiation?
    Cancer

    Or what

    Nsa radiating bones nervous system

    When pregnant

    V2k neuro link

    Now think last yrs

  6. I find your use of the word "white" extremely dismissive and disrespectful. You should be using the proper, inclusive term "European-Middle-Eastern-and-North-African-American."

  7. I find your use of the word "white" extremely dismissive and disrespectful. You should be using the proper, inclusive term "European-Middle-Eastern-and-North-African-American."

  8. I was born 1 & 1/2 month premature and I have suffered from respiratory problems all my life, asthma, limited O2 intake (breathing difficulties) etc. etc.. There are heaps of problems being born prematurely and its amazing to see .

  9. I performed my first phlebotomy procedure (venipuncture) today! You can checkout how nervous I was here: https://youtu.be/FlaqhoVOzlw

  10. In places outside the US, doctors can be very hesitant to prescribe antidepressants which I do not oppose but seeing how it can help people I think adding an objective test could be a barrier if it's not accurate or the bar is set too high so that they cannot try medications. Or maybe in countries where universal healthcare isn't a thing yet, insurance companies may set a threshold where at only that level of biomarker will the insurance company pay out. Also horror stories with terrible psychologists are not really rare, some just tell you to suck it up

  11. Ahh man, I'm getting weirder and weirder about Michael Aranda. I could listen to his voice all day. I want him to read a book to me.

  12. These tests are performed by Medical Laboratory Scientists! If you find this video interesting then the field may be for you. All the good feelings of helping people in healthcare without the patient contact

  13. Concussions are also huge when it comes to domestic violence and sadly is often overlooked when it comes to scientific studies regarding concussions and tbi

  14. The discovery of the link of low levels of acetyl-L-carnitine to major depressive disorder is truly ground breaking, as indeed, there has never been ANY blood test that could screen for something like this until now. (It's true usefulness still needs to be studied extensively.) Acetyl-L-Carnitine is essential for transporting fatty acids into the mitochondrion to be used as fuel, (which could explain the effects of its deficiency on fatigue and psychomotor retardation). There is a growing body of research on this, and many scientists realize more clinical trials are recommended. Here is a meta-analysis of some early clinical trials that have occurred so far: https://www.researchgate.net/publication/320645599_Acetyl-L-Carnitine_Supplementation_and_the_Treatment_of_Depressive_Symptoms_A_Systematic_Review_and_Meta-Analysis

  15. "Working to develop a test" is NOT something your blood can tell you, just something it might tell you in future. We don't know what initiates labor in the first place and we suck at stopping it so knowing gestational age is helpful how?

  16. so umm… the sixth time i lived in a psych ward, i stayed in a high-observation cell/room and i bashed my head against the wall as hard as i can over & over again for some stretch of time on many days… it became so noticed by the staff that they said they wouldn't come into my cell to stop me anymore but then i kept on banging my head on the wall so much that they finally came in again to check my eye dilation with a flashlight when my face and multiple walls were covered in my blood. Here's the thing though… my neuropsychiatrist, who was directing my care when i was there and is also still my neurospychiatrist, never had me get a CTE scan or CT scan or whatever since the bloody incident despite how much i asked him for one, saying i never showed any symptoms…. should i get my head scanned or my blood checked for signs of head/brain injury? my neuropsychiatrist sure seemed sure i didn't need to

  17. LAC? It is usually named ALCAR, even in studies I've read. r/nootropics have some posts about ALCAR, it is mildly beneficial for most people, I would call it "caffeine lite".

  18. Instead of fixing the socioeconomic system that favours psychopaths to fix the root causes of depression, let's come up with another expensive blood test so we can sell people even more expensive toxic patented drugs. Genius.

  19. I was born 2 months too early. Doctors said I wouldn't survive for more than 3 years, and if I did, I would be mentally and physically impaired… Today I am a teacher, and I am not impaired in any way.

    Glad to see science has come a long way since I was born

  20. I love learning about all the little bits floating around inside of me!! But, I don’t like seeing blood. In fact, I’m an adult human who loves science, but when people get surgery on tv I cover my eyes. 🙈 Just me?

  21. Go to http://Brilliant.org/SciShow to try their Casino Probability course. The first 200 subscribers get 20% off an annual Premium subscription.

  22. I'd like to point out That Distributing Phosphorus Into the vascular system By the cell Increases blood Flow Like an electric train You know a negatively charged Exterior And a positively charged Cell So if you put a bunch of trans fats that stick To the cell wall A bottle necks the blood flow And Depression Is your got bacteria telling you there's something wrong I like to think That reptiles are depressed until they get enough sunlight ..
    Back to the 1st topic If the most common version of cholesterol Doesn't convert into testosterone Do you do a factor like Cholesterol containing An endocrine disruptor That would have an effect on the fetus Development .. Does too much alcohol in the gut Destroys certain types of healthy gut bacteria If so what varieties What's the difference between city water in Flint Or Canada Per fluid ounce And alcolized water As it applies to Cell movement In a blood sample Versus alcolized water ??

  23. The levels of oxytocin, serotonin, melatonin, dopamine and a few other chemicals in the body and their imbalance is the major cause of depression symptoms. Don't really think a blood test is necessary to diagnose anxiety/depression when all those imbalances manifest as physical, emotional and behavioral symptoms that would be easier for a doctor to quickly diagnose.

  24. SHOW IDEA: Have you heard or done a show about the remission or development of schizophrenia through bone marrow transplants? NIH Study below…

    Remission of Psychosis in Treatment-Resistant Schizophrenia following Bone Marrow Transplantation: A Case Report … https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613125/

    The possible autoimmune system and mental health connection is mind blowing (pun intended).

  25. Before modern medicine things which would cause premature birth would likely result in the infant's death thus making sure the genes responsible would not be passed on to subsequent generations. With modern medicine tho, these genes survive and spread through the population. This is true for far more than just prematurity tho, take eyesight as another example. In pre-modern times bad eyesight could get you killed, now there is zero downside when glasses can give you 20/20 vision, thus there is no evolutionary pressure for humans to have good eyesight and the genes for bad eyesight spread. This is all part of the study of the accumulation of negative traits in our species called Dysgenics.

  26. I'm not a biologist or anything, but I'm pretty sure the most common abbreviation for Acetyl-L-carnitine is ALC, not LAC.

  27. Thumbs down because title not accurate. Title was 5 weird things your blood can tell about you. Discussion was 5 things blood may one day help diagnose. Interesting, but not what the clickbait title suggested. I expect better from Scishow

  28. Wow, the misinformation is so prevalent even SciShow got it wrong. Heart disease isn't the biggest killer.
    Aging is the #1 killer, and it is a disease, and there are a growing number of researchers working on ways to remedy this problem.
    (Edit: the misinformation quip was a sarcastic jab at social media and whatnot)

  29. The self reporting always can use a solid science backup to treat fakes for their faking, not what they fake with the number of people who lie regularly to get drugs.

  30. To know if your baby is going to be born early, you just need a good midwife who is also a gynaecology. Mine predicted, when I was 5 months pregnant, that he would be born 14 days early and she was right, down to the hour +5 minutes.

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