Hi All.
After another lengthy hiatus…I’m back at the keyboard. Here’s hoping 2024 brings us all good things.
I’d like to start the new year by saying a huge thank you to those who have posted comments and positive feedback on my blog. Your words are incredibly touching, and it warms my heart to know that even just a few people are benefiting from this project.
This latest post is focused on a topic that so many people living with Crohn’s and ulcerative colitis (and chronic illness in general) find confusing – blood tests and lab values.
I must preface this post by saying that, of course, I am not a doctor and cannot give actual medical advice. I have, however, had about a bajillion blood (and other) tests in my life…so I feel at least mildly qualified to talk about them.
Testing 1,2,3? Testing…
Picture this scenario: maybe right now you are in the midst of a flare. Or maybe you are in the initial stages of diagnosis. Your Gastroenterologist orders a bunch of tests. You have these tests done and get some results back.
Perhaps they are posted online. Maybe you are waiting to discuss the results with your GI. Or maybe you already did and you are still confused.
You think to yourself: What the heck are these tests for anyway? And what the heck to they mean?
Roll up your sleeve…
Likely, you will have some blood samples taken. In testing your blood, they will first do something called a Complete Blood Count (CBC). This test analyzes the different components in your blood: things like red blood cells, white blood cells, platelets, etc.
If you are experiencing a flare, then this test may show high white blood cells (often Neutrophils). A high white blood cell count may also indicate the presence of infection.
If you are experiencing any bleeding or ulceration in the digestive tract, then values for hemoglobin, hematocrit, and iron may be low (your body is using up iron stores to replenish lost blood). If your levels of blood iron fall below a specific threshold, you are considered anemic, and the physician may recommend iron supplementation or infusions.
Similarly, with bleeding, platelet levels may be high because the intestinal lining is trying to heal and clot. This is normal when you have active inflammation.
Blood tests may also analyze electrolytes. If you are experiencing frequent diarrhea or vomiting, blood levels of sodium, potassium, chloride, and bicarbonate can be low.
Often, they will test for C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). These are “nonspecific” markers of inflammation. Elevated or high levels of CRP and ESR can indicate that inflammation is occurring somewhere in the body, but do not provide information on where that inflammation is located (only imaging techniques like endoscopies, colonoscopies, and MRI/CT can do that).
Additional things in blood that might be tested for include:
- Serum albumin and prealbumin levels: low levels of these proteins may indicate malnutrition or protein deficiencies
- Vitamin B12: this may be low because intestinal inflammation can reduce body’s ability to absorb B12, which can contribute to anemia, neurologic, and other issues
- Liver enzymes (ALT, AST, GGT): these may be high when the body is “stressed” and dealing with inflammation and/or infection
- If you are on a biologic, they may also do a test to see if the blood levels of the biologic are within a specific “therapeutic range” (which can assist in optimizing dose).
The proof is in the poop
There is a good chance you will also have to submit a stool sample. Oh joy.
Here, they will likely test for Fecal Calprotectin (FCP), a protein released by white blood cells in the intestines. High levels of FCP suggest inflammation is occurring in the GI tract. Stool cultures may also be done to identify the presence of infectious agents such as bacteria (like c-diff) or parasites.
Final thoughts
There you have it. The tests listed above are the most common ones in my experience. There are tons of other tests they can do too. Hopefully your GI explains the rationale behind additional tests he orders. If not…ask!
One final word of advice: try your best not to obsess too much over blood values. And try not to go down rabbit hole too far and Google every possible cause of an abnormal result. I am 100% guilty of both of these, and trust me…it doesn’t help doing either.
Blood values may vary over time. They might be a little high one month, then normal the next month. Many will be “flagged” if they are even slightly outside the “reference range”. Often, the reference range can vary depending on your age, gender, and other factors. In a lot of cases, the values are only “clinically relevant” if they are waaay outside of the reference range.
Bottom line: your doctor will contact you ASAP if they feel something from a blood test needs to be followed up on. All the same, it is always good to educate yourself on what the different blood tests mean, so you can be an active participant in your own care and treatment plan. Knowledge is power:)
More information:
Table of normal ranges: https://www.ccpe-cfpc.org/wp-content/uploads/2018/03/normal_values.pdf
Additional explanation of tests: https://crohnsandcolitis.ca/About-Crohn-s-Colitis/IBD-Journey/Diagnosis-and-Testing/Blood-Tests