Getting your blood drawn for lab tests is something we all have to do from time to time. Whether it's a routine check-up, a direct-to-consumer blood test, or your doctor needs to investigate something, those vials of blood can reveal a lot about what's going on inside your body.
But did you know that how hydrated you are can actually affect some of those blood test results?
Getting your blood drawn while dehydrated can lead to incorrect results It's true! Being dehydrated when you get your blood drawn could lead to skewed readings that don't accurately reflect what's happening.
Here are some examples of how dehydration can alter certain test results:
Dehydration may elevate your hematocrit and hemoglobin levels Dehydration doesn't just concentrate certain compounds in your blood - it can also make it seem like you have too many or too few blood cells circulating. This is because dehydration reduces your total blood volume .
When you're properly hydrated, your blood cells (like red blood cells, white blood cells, and platelets) are suspended in plasma, the liquid portion of your blood. As you become dehydrated, you lose some of that plasma portion while the cell portion stays the same.
This increases the concentration of blood cells compared to the reduced plasma. On a blood test, it could lead to artificially high readings for red blood cell counts (hematocrit) or hemoglobin levels . Your doctor might think you have a condition like polycythemia (too many red blood cells) when you're simply dehydrated.
The opposite can also happen - if you're severely dehydrated, your red blood cells can shrink in size. They lose water and become smaller and denser, mimicking anemia (when your body doesn't have enough red blood cells).
The impact on dehydration in diagnosing anemia can be significant — one study in Ghana, where the population has low daily water intake, suggested that total blood volume must be assessed to properly diagnose anemia at all .
By staying well-hydrated before a blood test, your blood volume and cell counts should be accurate. This prevents your doctor from potentially misdiagnosing a blood disorder that doesn't really exist.
Dehydration can falsely suggest kidney problems The kidneys are the body's filter system - they remove waste and excess water from the blood to be excreted as urine.
When you're properly hydrated, your kidneys can efficiently filter your blood and remove just the right amount of waste like urea, creatinine, and excess minerals. But when you're dehydrated, the kidneys try to conserve as much water as possible.
This means the waste products become more concentrated in the reduced volume of blood going through the kidneys. On a blood test, it could show really high levels of things like urea nitrogen (BUN) and creatinine - making it seem like you have poor kidney function when you're simply dehydrated.
Dehydration can make your cholesterol seem higher than it actually is Cholesterol is another blood measure that can get thrown off if you're not properly hydrated for the test. Cholesterol travels in particles called lipoproteins , which circulate in the liquid plasma portion of your blood.
When you're dehydrated, your plasma volume goes down but the cholesterol particles remain the same. This leads to a higher concentration of cholesterol and lipoproteins compared to the reduced plasma .
On a blood test, your total cholesterol, LDL ("bad") cholesterol, and other lipid numbers may appear artificially elevated simply due to dehydration - not because there's actually too much cholesterol in your body.
Dehydration affects your blood test because it changes the concentration of biomarkers in your body Basically, when you're dehydrated, there's less fluid in your blood which can concentrate some substances and dilute others. This skews the numbers your doctor sees compared to if you were properly hydrated.
Throne can help make sure you’re well hydrated and get the most accurate blood test results So how can you make sure you're hydrated enough for accurate blood tests? An easy way is to use Throne! Throne analyzes your urine when you use the restroom to determine your hydration level. A Throne hydration score between 85-100 means you're in the perfect range to get a blood test done.
Not only that, but keeping your hydration consistent before each blood test by using Throne means your results over time won't be thrown off by hydration levels going up and down. That gives both you and your doctor a much clearer picture of what's really changing inside your body.
The bottom line is, being hydrated matters for blood tests! Using Throne takes out that guesswork so your results are as accurate as possible. That way, you can make the best decisions about your health and get things headed in the right direction.
