Blood tests are an invaluable way to assess various aspects of your health - this article will tell you how to prepare for a blood test for the most accurate results. Blood tests - the most common type of pathology test - are a relatively inexpensive way of assessing both your current health and potential future health issues you can use for preventative health care. Did you know that many variables can make the results unreliable and potentially dangerous? Now you do - so, read on to avoid the most common mistakes.
One of the main pitfalls of pathology testing is incorrect preparation. This can happen for various reasons, but the most common is that the patient (that's you!) hasn't been given good advice about how to correctly prepare for your blood test. Unfortunately, many doctors won't tell you that fasting is essential for most blood tests - yes, really! Being in a fed state - or even excessive fasting - will skew many blood markers, making the results quite difficult to interpret accurately.
My recommendations - how to prepare for a blood test
- fast for 8-12 hours before your tests*. Only consume water - no coffee or tea or anything “light”)
- inadequate fasting can raise levels of some nutrients, liver enzymes and white cell counts.
- avoid excessive fasting (anything over 12 hours) - this can raise some markers artificially such as those found in the iron studies panel. Obviously, there are times this is unavoidable such as if you're in hospital after an accident for example.
- avoid taking biotin for 3-4 days before the tests - often found in hair/nail formulas and multivitamins**. Biotin can affect the results of thyroid tests and potentially others.
- if you’re taking supplements and any of those nutrients are being tested (eg. iron or zinc), stop them 3-4 days beforehand
- avoid strenuous exercise for 48 hours before - this means anything that increases your heart rate or weight lifting. Walking and gentle yoga are fine. Do not perform any exercise except gentle walking on the morning of the test. Strenuous exercise and exercise in the hours before the test can affect liver enzymes, white cell counts, zinc, cortisol and many others.
- avoid alcohol for 48-72 hours before the blood draw. Alcohol can affect iron markers and GGT (a liver enzyme)
- try to always have your tests done at a consistent time or close to it eg. 8am or thereabouts. Many markers change throughout the day, so it's good to compare apples to apples by sticking to a consistent test time.
- drink 2 cups of water an hour or so before the test - this helps to hydrate your veins to help blood flow better and also minimises dehydration which can affect many markers
*the only exception here is if you have to consume something specifically for a test (eg. glucose tolerance test) or perhaps if you have a tendency to faint. Otherwise, fasting for tests is ideal because eating within 8-12 hours of testing can affect many markers (more than what most GPs are aware of)
**Biotin can skew many test results including thyroid markers and Vitamin D
Other tips for blood tests
- always get a print out or digital copy of your results to keep on file. Legally, once your doctor has talked you through your results, they are yours’.
- for those who experience anxiety around blood tests, breathwork is incredibly helpful and being well rested is essential. I recommend 4-7-8 breathing and others swear by alternate nostril breathing.
- If you don't feel well on the day of the test, see if you can reschedule it.
Need help interpreting your results?
You know the story - you go to the doctor because you're not feeling great. Your doctor looks at the results and tells you everything is "normal" - but is that actually true? It could be that there is indeed a problem lurking that isn't being interpreted correctly, especially when it comes to nutrition status. Doctors are medical professionals, they aren't nutritionists. I've lost count of the number of times I've picked up on problems that were previously missed or glossed over. Nutritionists and naturopaths can pick up on things that have been missed and we always have one eye on the individual's current health, and the other eye on future health.
I'm trained to interpret pathology from a nutrition and general health perspective and offer a Pathology Interpretation service that will help you gain essential insight in to your health.
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