What Should I Be Tested For?

Laboratory Tests for Vegans is an updated version of this article.

I am regularly asked by vegans what they should be tested for. Here is a run down:

Vitamin B12

As I say in Should I Get My B12 Status Tested?

Vegans do not need to get their homocysteine or B12 levels checked merely because they are vegan. Rather, being vegan means that you should get a regular, reliable source of vitamin B12 from fortified foods and/or supplements. (Though if you’ve gone a month or so without a reliable source of B12, you should replenish your stores as described in Step 1 of the Recommendations.)

About 2% of people do not absorb B12 well. While this has nothing to do with being vegan, it is nice to know if you are such a person. You will not be able to tell unless you first have a reliable source of B12 for at least a few weeks before your B12 level is checked. Additionally, there are specific tests that directly measure B12 absorption.

If you get your B12 level checked, please note that eating seaweeds can falsely inflate B12 levels. Methods for determining B12 levels do not distinguish between B12 and some inactive B12 analogues. Many seaweeds contain a variety of inactive B12 analogues. Someone who is eating large amounts of seaweed may have serum B12 levels well above normal, but much of it could be inactive B12 analogues.

Vitamin D

This is probably the one nutrient that vegans really can benefit from getting tested even if they do not have any symptoms of poor health.


The body keeps blood calcium levels relatively constant regardless of your diet, so getting calcium levels tested doesn’t tell you much of anything (other than that you are not seriously ill). Getting your bone mineral density tested is the best way to find out what shape your bones are in. I don’t necessarily recommend this, unless you have reason to believe you might have osteoporosis. I’ve said it many times before, but I’ll say it again – most vegans should drink calcium-fortified non-dairy milks (or other foods) or take a calcium supplement.


If you’re taking a DHA supplement, then you don’t need to be tested unless you suspect you’re having a cognition or other possible omega-3-related problem. Here are some testing companies.

There is a more common test that could shed some light on your EPA status—blood clotting time. Most doctors test for this routinely. If your blood is clotting too fast, you might be lacking EPA. I rarely hear from a vegan whose blood is clotting too fast.


If a doctor is going to draw blood, getting an iron panel to see if you have enough (or too much) iron is a good idea, especially for menstruating women.


There is no direct test for iodine. Like B12, it’s best to just make sure you’re getting enough (but not too much). Iodine deficiency (and excess) can lead to thyroid problems, so getting your thyroid tested would be an indirect indicator. Click here for more on iodine.

And that covers it for any routine nutrients to test for regarding the vegan diet.

30 Responses to “What Should I Be Tested For?”

  1. Colinski Says:

    Hi Jack, while you’re on the subject of D and Calcium, have you seen the stuff all over the news in the past day about new research challenging conventional wisdom in regard to supplementing those two things?

    Any thoughts?

  2. Jack Norris RD Says:


    I will post about that as soon as I get a chance.

  3. Putting the Late in Deflate « Pythagorean Crank Says:

    […] As the accounts of ex-vegans continue to pile up vegans are wiping the Ener-G from their face and scrambling to plug the nutrition gaps in the ill-advised health vegan’s knowledge. This may stem the eventual […]

  4. Joselle Says:

    Prior to going vegan (but in the early stages of me being vegetarian and soon after vegan), my b12 levels were well above normal. Just a year later–and after a year of being vegan–my B12 levels dropped from the 600 range to the 300 range. While this is still clinically considered normal, Sally M. Pacholok, RN, who coauthored the book, Could It Be B12 (http://b12awareness.org/) says anything below 400 should be considered a deficiency or at least the start of one. My homocysteine and methylmalonic acid levels were within normal ranges but this seemingly (at least to me) drastic drop in my B12 levels concerns me. I always took and continue to take a reliable source of supplemented B12 in the form of a multivitamin so it wasn’t that I wasn’t supplementing. I take a vegan multivitamin that has 25 mcg (313% of DV) of B12 as cyancobalamin. Pacholok argues this is not the most readily absorbable form (she recommends methylcobalamin instead) but it’s the one I always heard vegan nutriton sources endorsing. What’s your take on that?

    The last time I had my levels checked was in 2008. I’m going to go to my PCP soon to get it rechecked and go from there. I’m not a dietician or healthcare professional but I am currently a pre-nursing student with plans of being a nurse-midwife, so I’m studying anatomy and physio and nutrition right now. It does seem that in my case, my being vegan–and not just B12 absorption or lack of supplementation–had plenty to do with my B12 levels.

    I am still vegan and have been for nearly three years but I have been thinking about whether that’s something I’ll do long term given my last B12 results. Of course, if I can take different supplements, higher doses, a different form of B12, or shots and stay vegan, I would prefer it. It’s also possible that my B12 levels will be fine this next time around. That’s why I haven’t decided to stop practicing veganism without more current bloodwork. But it’s definitely something I’ve reconsidered since learning Pacholok’s perspective on B12 and relooking at my results.

    I’ve also spread the word to my mom since she’s over 50 and B12 absorption, as you well know, is not just a vegan concern but is also one for those of us getting older.

    Would love to hear what you think about this. Thanks for the helpful info on this site. BTW, my vitamin D levels were great!

  5. Jack Norris RD Says:


    If you take a chewable B12 supplement of 1,000 µg, twice a week, your B12 levels should be fine. I would disagree that there is any case for alarm that they dropped to 300. By the way, do you know the units they were measured in each time, and the units Pacholok recommends? B12 is typically measured in both pg/ml as well as pmol/l.

    1 pg/ml = 1.35 pmol/l

    If your homocysteine and MMA levels were fine, then there is really nothing to worry about as long as you up the B12 a bit. B12 from chewable supplements is much more easily absorbed than from animal products.

  6. Joselle Says:

    Hi Jack,

    The units were pg/mL. I’m not sure off the top of my head what units Pacholok recommends.

    I bought a chewable form of B12 but haven’t taken it yet because Pacholok recommended getting tested before tinkering around. I am going to get tested again and then go from there. For now, I’m still just taking my multi.

  7. Jack Norris RD Says:


    I wouldn’t put too much faith in Pacholok. I’ve never seen any peer-reviewed research indicating that someone shouldn’t tinker around with their B12 levels. Oh, I forgot to give you the link to the methylcobalamin information:


  8. Joselle Says:

    Hi Jack,

    Perhaps I phrased that wrong. She did not say that someone shouldn’t take B12 supplements or “tinker” around with doses. What she said is not to assume you have a deficiency without a test and then just take megadoses because you self-diagnosed. And, if you do suspect a deficiency, to not take megadoses before your test and perhaps skew results. She had pernicious anemia, has been an RN for many years and has studied B12. She was and is not vegan but doesn’t seem antivegan at all–just pro-awareness. In fact, I’d say she’s mostly preaching to nonvegans, especially since we’re more aware of B12 than your average nonvegan. Much of what she says seems sound. I figured another few weeks without chewables until I test again wouldn’t hurt since I’ve gone years without them.

    My recent little, little doubts of veganism hasn’t been just her work but also my current schooling and perhaps some paranoia from too much reading! 🙂 I’m just thinking and haven’t written off my 3-year, very heartfelt commitment to veganism by any stretch of the imagination.

    Thanks for your time and help with this. I’ll check out that link.

  9. Sayward Says:

    Joselle! So funny, I was reading this article and thinking of your email, then scrolled down to the comments and there you were. =D


  10. Laura Says:

    Can people be wiped out or brain fogged from iron deficiency, with low-normal hemoglobin? My hemoglobin was 12.3 g/dl, my hematocrit was 36.7% and my RBC’s were 4.01.

  11. Lisa A. Says:


    Do you consider zink to be an important mineral to be tested for? I had a low borderline reading when I checked last month. Although my husband had a level in the middle of the normal range.

    I also wanted to ask you about the lastest vitamin D and calcium report. I am looking forward to reading your post on that topic.

  12. Jack Norris RD Says:


    Plasma zinc is similar to calcium, unless you are severely deficient, it does not tell you much. There are many other ways to measure zinc, but the last I knew, none seemed to be considered reliable for determining the adequacy of someone’s zinc status. How were yours tested?

  13. Lisa A. Says:


    I had my blood checked by Kaiser. Here are the results:
    Zink -Your value: 61 – Normal Range: 60-130 mcg/dL

    Why is this not reliable? Can you recommend a website that has information about zink. I noticed that veganhealth.org has very little information about this mineral.

  14. Jack Norris RD Says:

    Lisa A,

    I just meant that your blood zinc level will not tell you if you are getting enough in your diet (and in your cells). As I explained above, it’s because the body keep the zinc levels in the blood fairly stable except in extreme situations. I would not consider a finding on the low end of normal to be indicative that you have a problem, but you could always take a modest zinc supplement for insurance.

  15. La Donna F Says:

    I followed the link to the iodine article and read it. I have a bottle of potassium iodide that says each pill contains 32.5 mg. Of potassium iodide and the article recommends a daily dose in terms of mcg amounts. I am not familiar with mcg. How often can I take these pills to keep my levels of iodine up? I also use iodized salt and live in the Midwest.

  16. Jack Norris RD Says:

    La Donna F,

    There is 1,000 mcg in a mg. Do not take potassium iodide for meeting iodine requirements as it is way too much iodine. Here is more information:


    If you use iodized salt, you should be fine.

  17. Lisa A. Says:

    Hi Jack!

    I decided to translate this post and include it on the website because so many people have asked me about this. I was wondering if you could include a note about testing one’s level of protein. I have heard someone mention that they did that. Although, I have never done it myself. Do you know anything about how such testing works?

    Also, maybe you could also include a brief note about zinc in your post. It seems to be a nutrient of concern in vegan diets and some people might be wondering about how they can check their level. At least it will be helpful for them to have some understanding about this.

    Thanks for your time!
    Lisa A.

  18. Jack Norris RD Says:


    It’s been a long time since you submitted that comment. I’m sorry it took me so long to put it through.

    Regarding testing for protein, there isn’t anything that is going to detect a mild deficiency, unless you have a nitrogen balance study done on yourself and that is pretty impractical. If you have fairly serious protein deficiency, then your blood albumin and prealbumin levels could tell you about long and short-term deficiency, respectively.

    As for zinc, as I’ve said elsewhere, there isn’t a good test for mild zinc deficiency. But if you are getting lots of colds, it might be something to consider. In recent years, I have been taking a calcium supplement that contains magnesium and zinc to make sure I’m getting enough. Probably not a bad idea for all vegans.

    The Linus Pauling Institute has a pretty good page on zinc here.

  19. Marek Says:

    My doctor has suggested measuring serum PTH as an indicator of whether one has enough calcium. What do you think of that?

  20. Jack Norris RD Says:


    I think it could shed some light on the situation, but cannot tell the entire story.

  21. Marek Says:

    Jack, why do you think it can’t tell the entire story? Is it because it can only show if there has been enough calcium in the diet recently, but not in the long-term?

    One hospital in Prague has recently opened some sort of nutritional advice bureau, where thorough blood tests are offered, the doctor there said to me yesterday that he has so far examined over 30 vegans and that an increased PTH is quite common among them. But I also know vegans who’ve been there and had normal PTH level even though they don’t try to include calcium-rich foods (so I’d guess their intake will be about 500 mg or below). So does it mean that some people are doing just fine on low calcium intakes and that the much higher recommendation is only made because some people need more? Or are there still reasons to worry even if PTH is consistently normal on low intake?

  22. Jack Norris RD Says:


    > Is it because it can only show if there has been enough calcium in the diet recently, but not in the long-term?

    That would be one thing to consider. But I was mostly thinking about the fact that vitamin D status can affect PTH levels. There are other things that can also (kidney disease and other diseases), but those should be minor issues in a typical sample of vegans.

  23. Jill Princehouse Says:

    Are there changes in CBC or other blood tests that indicate better health on a vegan diet (but worse health on a standard American diet?

  24. Jack Norris RD Says:


    I don’t understand your question.

  25. Jill Princehouse Says:

    Joel Fuhrman says a CBC with a wbc count in the 2s indicates health. What about other CBC values? Is it healthy if they are low by typical standards too?

  26. Jack Norris RD Says:


    I have no reason to think that any abnormal values in a CBC count would mean something different for someone on a vegan diet than for someone on a non-vegan diet.

  27. Marek Says:

    Jack, I’ve recently come back to this question while preparing a lecture about vegan myths: Is there any reason why someone with a low calcium intake but normal serum PTH and Ca levels should still increase their calcium intake?

    I know quite a few vegans who don’t eat any calcium supplements, calcium-fortified foods or high calcium greens (so I assume their daily intake could be around 300-500 mg per day) but have normal blood Ca and PTH levels. I understand this doesn’t mean that everyone can do well on such low intakes, but it makes me much less convinced than I used to be about encouraging all vegans to increase calcium consumption to 700 mg per day – especially since I feel a certain risk that it might do more harm than good in some cases (e.g. by possibly decreasing iron absorption). There are some practical reasons as well – we don’t have that many calcium fortified food and high-calcium greens in Central Europe.

    So I wonder whether regular checks for blood PTH and Ca levels first might actually be a better option – or at least a good alternative to – preventively struggling for 700 mg calcium per day.

    What do you think?

  28. Jack Norris RD Says:


    Good question. I searched for about 30 minutes online and couldn’t find anything that really addresses this question. I would feel more comfortable talking to someone who is an osteoprosis expert. I’m knee deep in other issues right now, but will try to get to this soon. If, in the meantime, you might want to write some osteoporosis experts at a University or a foundation you might be able to get an answer more quickly.

  29. Marc S. Says:

    Jack, I’ve seen B12 recommendations on your site recently and I must say I’m puzzled. I understand that US RDA may be too little, but most researchers recommend 5µg [which is already much more than US RDA], while veganhealth.com recommends 25µg. It’s five times more.
    I can’t seem to find anyone recommending such high doses, but I assume it’s all about: “we know it doesn’t hurt you to take more, so take more”.

    My question is: is 5µg per day [per pill] enough for adults?

    I live in Central Europe and we can’t even get pills with 25µg [there’s only 5µg pill B12 supplement here, and the label reads “take only 1 pill per day”], and taking 25µg worth of B12 would require us to take 5 pills per day, which is quite weird [and – also – not very cheap in a long run, which doesn’t help with convincing people to veganism. B12 is quite expensive here].

  30. Jack Norris RD Says:


    I suggest so much because getting B12 in only one dose at a time significantly inhibits one’s ability to absorb it. As you can see from my recommendations here:


    If you take your B12 in two doses per day, you only need 2 µg for each dose, for a total of 4 µg per day. Other health professionals have recommended as high as 250 µg per day in a single dose:


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