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How to Interpret Blood Test Results

Matt and I recently got routine blood tests done in order to get a discount on our health insurance, and when we got our results back, he mentioned how confusing they were. “I bet other people find this confusing, too,” he said. “You should write a blog post about how to interpret blood test results.” Great idea!

I learned quite a lot about blood tests and what all those numbers and acronyms meant when I was interning in a hospital during my masters program. I also spent some time during my corporate wellness internship working as a screener at office wellness events, which meant I did a finger prick test on participants, took a small sample of blood, and used a machine to check their cholesterol, glucose, and triglyceride levels. I also checked their blood pressure and took measurements like height, weight, waist circumference, body fat %, etc.

health screening

It’s so important to understand what all these different numbers and acronyms mean and how they impact your health. Here are some common labs you’ll see on a blood test, what they mean, what ranges are normal, and what to do if they aren’t.

**Just a note that I am not a doctor, and this post does not replace advice from your doctor or personalized nutrition counseling –with a dietitian that has your medical records and knows your personal history. Try everything I share at your own risk, and only after checking with your doctor. If your levels of any of these are high, your doctor is the first place to start! Also, these reference range numbers only apply to the U.S. – other countries may measure labs differently.**

TRIGLYCERIDES
Normal range: <150 mg/dL; Borderline high: 150–199, High: 200-499, Very high: >500

Triglycerides are a type of fat found in your blood; the level of triglycerides in your blood can indicate how effectively you process the fat in your diet. When you eat, your body converts calories it doesn’t need to use right away into triglycerides, which are stored in your fat cells until needed for energy between meals. If you consistently eat more calories than you burn, this can cause high triglycerides (hypertriglyceridemia), which are a risk factor for heart disease.

Lifestyle changes to make if it’s high:

pesto salmon with veggies

TOTAL CHOLESTEROL
Optimal: <200 mg/dL; Borderline high: 200-239; High: >240

Cholesterol is a fat-like substance that’s found in all cells of the body; even though it’s often demonized, it actually is quite vital to health! Your body needs cholesterol to make hormones, Vitamin D, and to digest food; the body can make all the cholesterol it needs, although there is also some cholesterol found in food.

Cholesterol travels through the bloodstream in small packages called lipoproteins. There are two kinds of lipoproteins that carry cholesterol: low-density lipoproteins (LDL) and high-density lipoproteins (HDL).

LDL CHOLESTEROL
Optimal: <129 mg/dL; Borderline high: 130-159; High: 160-189; Very high: >190

LDL cholesterol is usually called “bad” cholesterol, because a high level leads to a buildup of cholesterol in your arteries, which are blood vessels that carry blood from your heart to the body (and obviously shouldn’t be blocked by buildups).

HDL CHOLESTEROL
Optimal: >60 mg/dL; Poor: <40 (men) and <50 (women)

HDL cholesterol is often referred to as “good” cholesterol, because it carries cholesterol from other parts of your body back to the liver, where it is disposed of.

What’s the deal with all these numbers?
Recent studies are indicating that high total cholesterol might not be a problem after all, especially if the two types of cholesterol (LDL and HDL) are in balance and there are not an abundance of small, dense LDL. After all, cholesterol is vital for a number of body processes, including production of hormones and healthy cell formation. Some studies even show that
higher cholesterol can correlate with a lower risk of heart disease, and a recent study from UCLA found that the majority of heart attack patients (75%) admitted to their hospital did not have high total cholesterol – but they did have metabolic syndrome, which is the name for a group of risk factors that increases your likelihood of heart disease. (One of these risk factors is high triglycerides; the others include hypertension (high blood pressure), high fasting blood sugar, abdominal obesity, and low HDL (“good” cholesterol).

Save the eggs! It is often recommended to avoid egg yolks if you have high cholesterol – this is not advice I agree with, especially given recent research. It appears excess carbohydrates, especially those that are processed/refined, actually increase your cholesterol more than dietary cholesterol intake does. Plus – those yolks have a lot of really great nutrients in them (like Vitamin D)! And as for saturated fat, research has shown that when people with high LDL cholesterol purge their diet of saturated fats, they lower one kind of LDL, but not the small, dense particles that are linked to high carbohydrate intake and are implicated in heart disease. There is also a lack of concrete evidence showing that saturated fat intake (from real, unaltered sources – e.g. unprocessed food/animal products) leads to heart disease or increased mortality.

Lifestyle changes to make if your total or LDL cholesterol are high and/or your HDL is low:

  • Eliminate trans fat (here’s a blog post about what is trans fat and how and why to avoid it) – this has been shown to increase LDL, decrease HDL, and up risk for diabetes, heart disease, and cancer – yikes.
  • Reduce refined carbohydrate and added refined sugar intake (e.g. white flour, processed foods, packaged desserts, etc.)
  • Start (or be more consistent with) exercising!
  • Eat more fiber-rich foods (like fruit, vegetables, and whole, unrefined grains). Dietary fiber reduces cholesterol because it carries some cholesterol out of the body with it.

scrambled egg muffins

FASTING BLOOD GLUCOSE
Ideal range: 70-99 mg/dL; Prediabetes: 100-125; Diabetes: >126

Glucose is a type of sugar that serves as the main source of energy for your cells, and this test will screen for problems in the way your body processes sugar. When you eat carbohydrates, your body will absorb glucose from the food, which increases your blood sugar. The body uses what is needs and stores some for later, too, and when it’s done, your blood sugar should go back to normal. The problem is that sometimes this system can go a little haywire, particularly (in the case of Type 2 Diabetes, which is heavily lifestyle-related, unlike Type 1 Diabetes, which is an autoimmune disease) if you eat a large amount of sugary, processed foods, do not exercise, and are overweight. A fasting (meaning you haven’t eaten in 8+ hours) glucose level above normal ranges is called hyperglycemia and may suggest diabetes. If you have hyperglycemia, this means that your body is either not correctly producing or using insulin, which is a hormone that enables your body to use glucose.

If your fasting blood glucose is high, the first thing to do is talk to your doctor about whether medication is necessary. In terms of lifestyle changes, here are some things to do that will help if you have (or are at risk for) Type 2 Diabetes:

  • Start exercising. (You saw this coming!)
  • Make sure that you are pairing carbohydrates (e.g. fruit, bread, grains, starchy vegetables like potatoes) with protein (meat, fish, eggs, etc.) and healthy fat (nuts, seeds, oils, avocado). The blood sugar rise effect from carbs will be slowed and mitigated a bit by the presence of protein and fat. Plus, pairing those three things will help greatly with satiety!
  • Reduce stress (stress can mess with glucose levels).
  • Sleep more (not getting enough sleep can mess with glucose levels AND increase cravings for sugary food – double whammy).

Related: While we’re talking about diabetes, a lab that is particularly helpful for determining your long term blood sugar control is Hemoglobin A1C (abbreviated HbA1c). Hemoglobin is a transport protein that carries oxygen through your blood. Glucose (sugar) in the blood after you eat normally becomes stuck to hemoglobin molecules, which are called glycated hemoglobin. Normal levels of glucose produce a normal amount of glycated hemoglobin, but as the average amount of blood glucose consistently increases, so does the amount of glycated hemoglobin, which serves as a marker for average blood glucose levels over the 2-3 months prior to the measurement. Normal range s: If you have diabetes, the HbA1c goal is <7%. For people WITHOUT diabetes: 4% – 5.6%. Increased risk for diabetes: 5.7% – 6.4%. Levels of >6.5% indicate diabetes. The higher the HbA1c, the greater the risk of developing complications related to diabetes.

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BLOOD PRESSURE
Ideal range: <120/80 mm Hg. Prehypertension: 120-139/80-89, Hypertension stage 1: 140-159/90-99, Hypertension stage 2: >160/100. Emergency: >180/110.

Blood pressure is the pressure being exerted on the walls of blood vessels/arteries by circulating blood. The top number in blood pressure readings refers to your systolic blood pressure, which measures the pressure on the arteries when your heart beats (contracts). The bottom number, diastolic blood pressure, measures the pressure when your heart relaxes (in between beats). If your blood pressure reading is high, it does not necessarily mean that you have high blood pressure – blood pressure can change quickly due to exercise, stress, sleep, and even posture – but your doctor will likely want to take more readings over time. If readings stay high over time, then that will indicate hypertension (which is a fancy word for high blood pressure – hypotension is the term for low blood pressure).

High blood pressure results from a combination of things, but being overweight and inactive are among the biggest factors that you can do something about (genetics, age, and race are also factors).

Lifestyle changes to make if it’s high (after talking to your doctor and seeing if medication is necessary):

  • Start exercising (or do it more frequently – see the end of this post for a link to a post about how to not hate exercise).
  • Reduce the amount of salt in your diet. I’m not a dietitian that is overly concerned with salt intake, and I don’t recommend obsessively tracking milligrams of sodium – the main thing you should do here is to reduce your intake of processed foods. If you eat real, minimally processed food you won’t need to worry about salt, because the main high sodium offenders are processed foods like frozen dinners or canned soup. If you do buy a packaged product, look for a low sodium version, and make sure the ingredients label is short and filled with things you understand. (See also: How to Add Flavor to Meals Without Sugar or Salt)
  • If you smoke, stop. (!)
  • Maintain (or get to) a healthy weight.
  • Decrease alcohol consumption (to no more than 1 drink per day, maximum. If you are already consuming less than this, great!).

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ANEMIA-RELATED MEASURES
(CBC, Hemoglobin, Hematocrit, MCV, Serum Ferritin, B12, Folate)

These tests are all related to anemia, which is a condition that develops when the body does not have enough healthy red blood cells or hemoglobin, resulting in your cells not getting enough oxygen. If you are anemic, you will feel lethargic and tired.

Anemia can be caused by several factors, including blood loss (which is why women of childbearing age are more susceptible to being anemic), decreased or faulty red blood cell production, or destruction of red blood cells.

One of the most common types of anemia is iron-deficiency anemia, which can result from the following (in addition to some digestive conditions, surgical removal of the stomach/intestine, and certain drugs):

  • An iron-poor diet (especially common when you are growing because your needs are higher (infants, children, teens), or if you are vegan or vegetarian because animal products are the best sources of dietary iron)
  • Pregnancy/breastfeeding (the metabolic demands for iron are higher)
  • Menstruation (because you are losing iron in your blood)
  • Endurance training (the stress you are putting your body requires extra iron. This is why anemia is common in runners! And why you sometimes crave a burger or steak after a long run.)

Another common type of anemia is vitamin-deficiency anemia, which can occur when dietary vitamin B12 (found in animal products like meat) and folate (found mostly in legumes and veggies) are deficient, as these two vitamins are needed to make red blood cells.

This sounds complicated – how do I know if I’m anemic?

Your doctor may do a Complete Blood Count, or CBC, which measures different parts of your blood, like the number of red blood cells, white blood cells, and the platelets in your blood. The CBC also measures your hemoglobin and hematocrit levels. Hemoglobin, like I mentioned previously, is an iron-rich protein in red blood cells that carries oxygen through the blood. Hematocrit measures how much space red blood cells take up in your blood.

The CBC also looks at Mean Corpuscular Volume (MCV), which is a measure of the average size of your red blood cells – this result can give an indication as to the cause of the anemia. (In iron-deficiency anemia, for example, red blood cells are usually abnormally small.)

If the CBC results confirm you have anemia, then you usually have other tests done to find out what is causing it and how severe it is. These tests include serum ferritin, which measures how much iron is stored in your body’s tissues, not just in your blood.

I’m anemic – now what? Beyond supplementation (talk to your doctor to see if that is necessary), here are some dietary recommendations:

  • If your anemia is caused by iron-deficiency, eat more foods that are rich in iron. Iron from animal sources, like meat and fish, is better absorbed – but nonmeat foods like legumes, tofu, dried fruits, leafy greens, and iron-fortified breads and cereals also contain some iron.
  • Pair iron-rich foods with those that contain vitamin C (e.g. citrus fruits and vegetables) – the presence of vitamin C enhances absorption of iron. Example: squeeze some lemon on your sauteed spinach and/or steak. My Orange Lemon Chicken recipe is another good option here, as is a simply baked fish in foil topped with some lemon juice, lemon slices, herbs, and olive oil.

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Another test worth mentioning:

  • Vitamin D (25-hydroxyvitamin D) – This isn’t normally included on a routine blood test, but it’s worth having it tested, especially since many people are deficient nowadays. If your levels are low (<20 ng/mL), it manifests in feeling sluggish and achy, and can also lead to more serious conditions like osteoporosis and other bone problems. Depending on the severity of the deficiency, supplementation might be required, but your body can also make Vitamin D itself from the sun if you get enough sunshine – so get outdoors! In terms of food, naturally Vitamin D rich options include egg yolks (again, save the eggs!) and fatty fish (tuna, mackerel, salmon, sardines). In addition, milk and soymilk are often fortified with added Vitamin D.

And there you have it! I tried hard to include some good, concrete information about what all this stuff meant without getting TOO technical or overwhelming, so I’m hoping I succeeded and you found this at least a little bit helpful. Bookmark it for future reference and stay healthy, my friends! Here are some other posts you might find helpful:

Comments

  1. 1

    THANK YOU for this! I am saving this post. I havent gotten blood work done in ages, but I do remember that when I did get it done, I had no idea what anything meant!

  2. 2

    Maybe you mentioned this in your post, but some of these numbers only work for the US. In Canada blood sugar is is measured differently and an ideal range is in the single digits.

  3. 4

    Great information! I love your blog and have been reading for over a year now and I think this is one of the most beneficial posts you’ve shared with us (you know, besides all the recipes!). Really helpful, thank you!

  4. 5
    Elisabetta says:

    Great Anne !! You gave very clear and well explained directions, that enable everyone to understand the results of their blood tests, and how many interesting tips!! The whole is also a help to acquire more knowledge and keep the brain trained !! Keep it up!!
    Elisabetta
    P.S. late but happy birthday to your blog!!

  5. 6

    Great post – very easy to understand and relatively free of technical and scientific language. As a physician (and a hematologist/oncologist) though, just a few comments:
    1) Anemia is not just due to iron deficiency, although it is the most common, especially in your readership. However, I disagree with a blanket statement that you should eat more iron because you are anemic – that would only help if you are iron deficient. Going along with that, we actually don’t use serum iron levels for any part of a diagnosis of iron deficiency anemia and we always start with a ferritin level. Transferrin and other labs such as TIBC (total iron binding capacity, which is NOT the same as transferrin, just to clarify) can help but it’s really the ferritin that we start with.

    2) I am a little hesitant of your comment regarding decreasing alcohol consumption to no more than 1 to 2 drinks per day. No guidelines or recommendations recommend 2 drinks per day – that comes out to the equivalent of 14 drinks/week which is harmful, both in terms of weight, blood pressure, cardiovascular disease, cancer risk etc. Even the most liberal guidelines tend to stop at 1 drink/day but even that increases your cancer risk in certain cancers.

    From a nutrition perspective, this is a fantastic post because it really shows people how to make lifestyle and dietary modifications but I urge you to be careful with a few more ‘blanket’ statements that you make and at the end of the day, patients should consult with their physician, nutritionist etc who has their medical record prior to making any lifestyle or dietary modifications.

    • 7

      Thank you so much for this insight – very helpful to have a professional’s insight as I am obviously not a doctor. I’ll update the anemia section per your comments – thanks! And regarding #2, I absolutely agree – I’ll decrease it to 1/day, with the note that obviously that’s a max and it’s not recommended to start drinking that much if you aren’t already. And absolutely agree re: your final statement, as I noted at the start of my post – this post is not a substitution for medical advice or personalized nutrition counseling.

    • 8

      I completely agree on everything you said. A CBC can be the start of noticing something is wrong but really it comes to an iron panel and focusing on ferritin and TIBC. I also think it’s important to note that GI bleeding is one of the biggest causes of iron deficiency anemia so figuring out WHY someone is iron deficient is so important. Furthermore, there are so many reasons why one could be vitamin deficient that need proper investigating.

      Also, although <129 is considered normal for LDL, a real goal is actually <100.

      The alcohol is actually a really important note you made because 14 drinks/week would raise my concern with my patients.

      All in all a great post but I

  6. 10

    Wow Anne, great post. A really great synopsis and summarization for blood work. I agree that is it often impossible to read these tests, and I think this post provides a great starting point to interpret the results. I really like your approach to food and exercise, but in this case, I’ll focus on the food. I really like that you have your clients focus on whole, unprocessed clean foods rather than calories. I also like how you mentioned the important benefits of eating the yolk of an egg above. When people don’t eat that, they are missing out on key nutrients of the egg that they are eating to be “healthy.” I like how you pointed out cholesterol is a good thing, I agree!! Hopefully people will look to other parts of their diets when cholesterol is high rather than immediately assuming egg yolks. Really great, informative post.

  7. 11

    Your husband was right – great post! This information is so helpful. I have been wanting to get my blood screens done for a while Saving this for future reference.

  8. 12

    Great article, Anne!! This was a great refreshment of what I learned in my undergrad Nutrition studies. Also good to read it again.

    Were you pleased with your results?

  9. 14

    As a type 1 diabetic, I think your explanation is a little lacking in that you don’t specify that you’re talking about type 2 diabetes. While too much weight and too little exercise — in conjunction with genetic factors which is often forgotten — can cause type 2 diabetes, it doesn’t cause type 1 diabetes. The diabetes community could use as much help as possible from influential healthy living bloggers such as yourself. In the future, if you could specify the differences, that would be great. Thanks. :)

  10. 16

    Thanks Anne – that is a great post! Sometimes when you’re in the consultation with your doctor and they start talking through all the results and numbers, it can be hard to keep up and make sense of it all. This post will be a great reference to remind yourself of what it all meant, as well great tips on how to make lifestyle changes, instead of always jumping on the medication bandwagon (although there is obviously a place for this where the situation warrants it). Knowledge is power, and I appreciate you sharing yours!

  11. 17

    Thank you for this post – very helpful! I also recently got blood work done, and I found out that I have elevated Vitamin D (>100) and was wondering if you knew of any foods that might be influencing this. I do not take any vitamins, nor do I live in a climate with lots of sun (I live in the northeast and I work in a windowless office 40 hrs per week). Additionally, I don’t eat eggs, rarely eat fatty fish (maybe 10x per year), and have minimal milk (<8oz per day). Any suggestions??

    • 18

      That’s interesting. Did your doctor comment on potential causes? Elevated Vitamin D is most likely not nutrition/food intake related, so it’s probably something more medical, which I wouldn’t be able to help with. I’m sorry! One thing I have seen noted, though, is that frequent use of antacids can cause elevated Vitamin D. Not sure if that could be a factor in your case. Good luck!

  12. 19

    Brilliant post! So many people misinterpret cholesterol results particularly…even doctors in Ireland are not giving advice in line with the most recent research! Hope things are changing your side of the water!

  13. 20

    Such a helpful post, thank you!

  14. 21
    Stephanie Hance says:

    Good post. It’s nice to have it all in one place because the information out on the “wild internets” is scattered and conflicting. My company requires us to do yearly physicals now and we lose all our HRA money if we don’t meet those “metabolic syndrome risk factors” so it’s nice to know what they’re going on about.

  15. 22

    To echo everyone else, GREAT post! If you do another results interpretation post, I’d love to read one about thyroid. Thanks!

  16. 25

    This post could not have come at a more opportune time as I am awaiting the blood test results I have this past friday. I will definitely look back at this post when I receive them to better understand what I am reading. Thanks!

  17. 26

    GIRL THIS POST should go VIRAL because SO SO SO many people have difficulties deciphering what their blood work means, and their doctors never have enough time to really explain anything!!!!

  18. 27

    Great post! Thank you!

  19. 28

    Such a great post. Thank you for all the helpful information. I am just wondering about low blood pressure. What does it mean? Is it something to be concerned about? Could it simply be something to do with genetics as well? Or, are numbers lower than 120/80 still ideal? Thanks in advance!

  20. 33

    Great post Anne! This is a confusing topic for a lot of people.

  21. 34

    Great post! I recently had complete blood work, and my doctor gave me a book (literally) on every finding. It was SO helpful! I was Vitamin D defiecient and am now taking a supplement. I read a lot about it, and most posts (by nutritionists/doctors) indicated that it was almost impossible to make up for a deficiency by food and sun alone.
    I really learned a lot in the process and appreciate your post. It is so important to get tested!

  22. 35

    Great post, I think sometimes the medical jargon can be difficult for most people to understand. As an RD who has worked in a hospital setting for 4 years I definitely have a lot of experience helping patients understand their labs and loved how you presented the info.

  23. 36

    Nice post and reference to what all these blood tests mean. It is quite fascinating what evidence research is showing when it comes to cholesterol and heart disease. The research relating to nutrigenomics and how genetic make up of apiloprotiens that are unique to the individual are becoming more reliable predictors of individuals who are more susceptible to coronary artery disease. Pretty impressive research out there on this topic.

  24. 37

    We have adopted “Burger Long Run” nights in my house after I do long runs of 13.1 or more…and it was all because I always crave burgers after long runs!

  25. 39
    Doreen G. says:

    Thank you so very much, Anne! So clear and informative. I’m bookmarking this for reference ease. I thought I understood the doctor’s explanation of my last physical’s test results but now I can go back over them and take my time and really map out a good plan. You took the time that we probably all wish our Dr. could take with us!

  26. 40
    Elisabeth says:

    Good idea for a post. I’m actually a clinical lab scientist & running all those lab tests is what I do for a living!

  27. 41

    seriously fantastic post!! i have been interpreting far too many results lately and finding out what everything means is such a bear! This is great!

  28. 42

    Super helpful post Anne! I’ll share it with some fellow health and wellness coaches as a quick reference guide :) I think it would also be great to add thyroid since that can also be really confusing for people x

  29. 43
    Roadrunner says:

    Great guide for all of this!

  30. 44

    Thank you for posting this. I have featured this article on my blog. I would like to discuss a possible collaboration with you since you inspired me to start blogging for my nutrition experience.

  31. 45

    Thank you for such a great and helpful post.

  32. 46

    As a medical student I think this post is great. Very informational, little jargon, and suggestions that everyone can understand. I did want to point out that while the numbers you list here are the “norms” (and what they teach us in school), depending on what lab you go to their values may differ (usually slightly, but sometimes to a large degree!) So when you get your results back, they should give you, next to your value, a range of normal values for that test for that lab. Just a heads up!

  33. 48
    Jen Powell Robinson says:

    Great post! A good reminder for me to go get a blood test done. I can’t remmeber the last one I did- maybe when I was pregnant? Anyway also a good page to bookmark for value references. Thanks :)

  34. 49

    Thanks for this, it was an awesome, informative post! I am going to pass this on!

  35. 50

    For the general public I think you did a great job! There are always exceptions in medicine but that is why we take general information and go to our doctors and talk about it. Great job!

  36. 51

    Hey Anne- great post!! I really like your explanations on cholesterol and often wondered why heart disease has not been drastically reduced with the over use of statin drugs? If the cause of heart attacks is because of high cholesterol, than why hasn’t the rates of heart disease gone drastically down?? Also, one thing about low vitamin D levels and the use of statin drugs. Two years I had my vitamin D level checked and it was 80, which is great. I also have high cholesterol so my doc put me on a statin. I had my vitamin D level checked last year and it went down to only 10! I did some research and found that alot of the vit D deficiencies are being caused by statin drugs because vit D needs fat in oder to be utilized by the body! I went off the statin and had my level rechecked and it is now 45. I have learned that statins are not the wonder drug they have been made out to be, and in fact, could be doing alot more harm than good! A great book to read is “Grain Brain” by Dr David Perlmutter. In the book he talks about fat, statins and brain health. Very interesting reading!

  37. 53

    Dear Anne,

    I strongly disagree with one sentence in your blog: “If your fasting blood glucose is high, the first thing to do is talk to your doctor about whether medication is necessary.”.

    It should be the opposite, first see what changes you can do to your life style before taking any medication. I was 25 yr when my doctor offered medication to treat high glucose sugar levels, he also gave me the option to eat less sugar (or none) and exercise regularly. I took the second option, I usually call it the long and hard way. I’m so happy I took that route, I haven’t had any problems for the last 10 years.

    Most problems with sugar are caused by bad diet and lack of exercise, and I see it happening more and more frequently between young people. Medication should be the last resort option. Watch what you eat and please read the labels when you buy processed food, sugar is everywhere.

    I would say, take control of your life instead of letting medication take control of you.

    All the Best. Anne D.

    • 54

      I 100% agree that lifestyle changes should be made first if they are an option. I just wanted to make sure people talked to their doctor about whether medication was or was not necessary.

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