Pernicious Anaemia Society
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I'm dealing with hypoxia lately. It sucks. And, unfortunately, I keep having to field questions like, "Is it because you take so much B12?" or "Is it because you switched from cyanocobalamin to methylcobalamin?".

I can only answer, "I don't think so", but, really, how am I supposed to know? I do suspect that it isn't a consequence of B12 deficiency, but I don't know (yet) what is causing it.

I've been going through various testing. The hypoxia was discovered after I was sent to see a cardiologist. Thankfully I have no heart problems. My lungs seem to be functioning all right as well. Since there are only three systems in body that are involved with getting oxygen to the tissues, and problems with two of them have now been ruled out, by process of elimination that means it has to be a blood problem.

I'm not anemic though, so that complicates the picture. There was a peripheral blood smear done that showed hypochromia, so that supports some type of hemoglobin problem. I have an appointment with a hematologist on May 5th. (I had to specifically ask for a referral because the cardiologist looked for a blood problem himself but was stumped by my results.)

I'm trying not to get my hopes up too high. I've seen two hematologists in the past and both of them blew me off because I wasn't anemic. One of them told me I couldn't possibly be having the symptoms I was describing with my test result numbers. So I know from experience how focused on numbers hematologists can become.

On the other hand, I really really need someone to get to the bottom of my problem and help me fix it. And I am hoping that the multiple demonstrations of hypoxia when moving around along with the blood smear will be enough to finally reach a diagnosis. Wish me luck. I'll let you know if I find out anything.

Btw, my oxygen levels are normal when I am sitting still. The problem was only discovered because the cardiologist asked me to walk up and down some stairs with a pulse oximeter on. He told me that my oxygen percent shouldn't fall below 94% but mine fell as low as 85%. On a later occasion it fell as low as 83% (then the oximeter started beeping in alarm so I stopped rather than find out how much lower it would go if I continued).

I don't actually know what level below 94% is a level that requires treatment, or what kind of treatment would be helpful. Does anyone know this? I've been assuming that I need to have the source of the problem figured out first, before any kind of treatment would be offered. But I've been having problems since February, and it's not getting any better on its own.

I don't know what I'll do if the next hematologist tells me that I can't be having symptoms because I'm not anemic... :(

14 Replies

Just a shot in the dark - could folic acid be masking anaemia?


I don't think it is. These are some of my results (reference range in parentheses):

serum B12: >1000 (239 - 931)

folic acid: 17.3 (>2.79)

serum iron: 61 (30 - 80)

TIBC: 280 (260 - 490)

iron saturation %: 22 (15 - 50)

ferritin: 39 (6.2 - 137.0)

hematocrit: 39.9 (34 - 46)

hemoglobin: 13.3 (11.3 - 15.5)

RBC: 4.68 (3.70 - 5.10)

I'm really just not anemic at all according to my blood tests. And, even though the blood smear showed hypochromia, it didn't show any unusually shaped or sized cells. They were normal sized but pale. It's just weird.


Have you got a MCV and MCH result?


MCV: 85.1 (80 - 100)

MCH: 28.3 (27 - 34)


Do some of those tests seems toward the low end of normal? I can't judge, but if it were me, I would specifically be curious about that and would want the doctor to discuss this.

Can I ask what your symptoms of hypoxia are? I wonder about this myself, but my tests are always normal.


The first symptom I noticed was fatigue. The kind of fatigue where all you can think about is laying down and sleeping (or you fall asleep even when you're trying to stay awake). After that I noticed that my legs felt weak and shaky if I was standing for more than a couple of minutes. I slowed down physically quite a bit because it felt like my whole body was made of lead. After that I started getting headaches and dizzy spells.

One symptom that I have been having but didn't realize might be a symptom is a tightness around my ribs. It's not something I would really think of as shortness of breath, because I can still take a breath without difficulty. It honestly feels more like my clothing has suddenly become too tight (but it comes and goes throughout the day and clothing usually doesn't change size like that).

I guess none of my results strike me as lowish because I've seen them be lower before. I'll have to wait and see if the hematologist can make heads or tails out of my confusing results.


Thanks for this. I hope you feel better.


Hi Galixie to metabolize B12 iron levels should be 100, could you ask your GP to bring your levels up, mine were deficient at 10, now taking iron and  levels raised to 27 at last blood test, symptoms improving hoping will get even better as GP agreed to get them up to 100. I was also not anaemic but had anaemia symptoms, dizzy, short of breath, no energy. Hope things improve for you. 


Hi, don't know if this helps but when I had a ferritin level of 30, tests showed I was anemic,  but I was also on the low side with B12, so don't know where exactly anemia cane from-lack of iron or B12 or both.

I was very tired and my Legs felt shaky when I tried to stand for just a few minutes. When you wrote that, I though of my ferritin deficiency. 

My new doc said even though the ferritin was within range, it was not optimal and so I have been on iron tablets, Solgar Gentle Iron, 25mgs, twice a day, which does not cause me any stomach problems. When my ferritin went up 4 points, I felt much better. But I also started having B12 injections at the same time, so it was not a good experiment! I think she would like to see my iron around 50 or 60?  It takes a long time to bring it up. 

Perhaps, even though you aren't anemic, you are feeling the effects of less than an optimal level of ferritin. Everyone is different and maybe what would be a good level for me is too low for you. Just an idea. The Solgar tablets are such a low dose that you probably would not be at risk for increasing levels too much. You can get them on Amazon. I'm not a doc but perhaps you could try this? I felt better after 2 weeks on the iron.

What a mystery!  Good luck!


Well I didn't get told that I couldn't be having symptoms because I'm not anemic. I suppose that's something. On the other hand, the hematologist is certain the hypoxia is either a heart or lung problem and he had no explanation for my normal sized hypochromic cells. He thinks the hypochromia is unrelated to the hypoxia. So that appointment was a bit of a bust.


OMG You have the exact same symptoms as my husband he has b12 def level 111. Been in hospital twice no diagnosis

Had liver test, heart, COPD, Xray lung all clear now going for for CT LUNG SCAN. All because of breathing issues. GP wanted to put him on antidepressants sertraline we said no way.

He has b12 Loading doses and one injection every 3months. The breathing problems have made him want to give up he has had enough. CLINICSL SPECIALIST measured his oxygen levels seated normal then walked up and down corridor dropped to 80.

Pleasel let me know how you are and if you have found out anything xxx


I really haven't made any progress on finding out what the cause is. After the hematologist decided that it must be someone else's specialty, I did go see a lung specialist. However my hypoxia episodes are intermittent and impossible to predict so, on the day of that particular appointment, I happened to not be having trouble with it. Since I couldn't demonstrate the problem in his office, he told me to schedule an appointment for when the problem is actually happening. But I am not psychic enough to know when it is going to happen to schedule an appointment for that time. So I've never gone back.

I know the problem still exists. I was in a car accident in November and I went to the ER. They hooked me up to the pulse oximeter (routine practice) and it alarmed multiple times in the hour and half that I was there. The nurses never did anything about it though because I was conscious and "didn't appear to be in distress". ::: eyeroll ::: I watched my oxygen level drop into the 60's at one point. I think the nurses just assumed the machine was malfunctioning or something. It made me wonder why the heck they bothered to hook me up to it if they didn't think it worked?

I hope your husband gets some answers. Let me know what you find out. :)


Did you have breathing issues before receiving b12 shots. Do you remember your lowest level of b12? Thanks for your earlier reply. Xx


I not sure I would have described them as breathing issues, so I can't say for sure. My B12 level just before starting treatment was 220 (211 - 911 pg/mL), so I was still considered to be in the 'normal' range, but my fatigue at that point had become marked and I couldn't walk up a flight of stairs without needing to rest once I got to the top. The B12 really gave me a remarkable recovery from that fatigue.

I suppose it is possible that I've had hypoxemia for the entire time and just didn't know it because I was never asked to walk around with a pulse oximeter until last year. All I really know is that it's still an ongoing mystery issue.


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