High MCH/MCV

[JanD236]

I’ve had PA diagnosed for about 5 years now and have settled on a weekly si regime, with a monthly hydroxy prescription from my GP.

I feel generally fit and well, maybe more tired in the evenings than friends of a similar age. I’m careful to rest after activities and when I feel tired.

I’ve just had my annual blood tests (mostly to check hormones and thyroid as I have Graves which is currently in remission) and my GP is happy to do other tests at my request (although she wasn’t at all happy at my refusal to have B12 tested).

All test results have come back in the normal range with the exception of MCH which is slightly high. Relevant results are

MCH 32.3 (27.5-32.0)

MCV 98 (84.0-98.0)

Folate 19.1 (3-20)

Ferritin 93 (10-200)

RDW 14.2 (<14.5)

MCHC 331 (300-360)

In previous years my MCH has been in range but my MCV above range. B12 was >2,000 last year.

I’m curious as to why MCH/MCV would be consistently at the top/above range when B12 is adequately treated, folate levels are great and other factors are all ok (thyroid & oestrogen levels).

I don’t suppose it matters if I feel mostly ok but if anyone has the answer I’d be interested to know.

[Raclette67]

Hi Jand. I have just posted exactly the same question. Let’s hope I get a reply so look out! I treat with regular injections but feel terrible at the moment. I was wondering if it was the high mch and mchc.

BW

[Sairbear1]

Interested in this post as my MCH/MCV have always been at the top end of the scale. Sometimes just over with an exclamation mark next to it but i’ve always been told to ignore that as it’s ‘normal’. 🙄

[FlipperTD]

Hi.

Your MCH is marginally raised and this reflects the fact that our MCV is sitting at the top of the range. The ranges in use are typically 95% ranges. (mean +/- 2 Standard Deviations). This means that of 20 individuals, 1 may be outside the range whilst still being normal.

The more numbers we generate, the more chances we have of finding one outside the reference range. The MCH and MCV will 'go together', and the relationship between them is the MCHC. (If you divide the MCH by the MCHC you get the Hb.)

The typical cause of a raised MCV (and therefore MCH) is usually megaloblastic change in the bone marrow, related to deficiency of B12 and/or folate. When any deficiency is corrected the MCV will also correct. Whilst this is happening, the RDW will increase, and then normalise again, over a period of a few weeks.

An increased MCV can be seen in thyroid disease, unrelated to any vitamin deficiency. Increased intake of alcohol can also be reflected in a raised MCV.

I write as a scientist, not a doctor, so I can't offer medical advice.

I hope this helps.

[JanD236 in reply to FlipperTD]

Yes that’s helpful, thanks for taking the time to reply.

As my MCV/MCH and RDW have all been consistently towards the top of the ranges, or just over, for the last few years and I feel that my PA is as adequately treated as it’s going to be I guess the likely answer is thyroid (I don’t drink much alcohol).

My TSH hovers around 4 (top of range 5) and Free T4 around 11 (bottom of range 10) and I have the relevant antibodies for Hashimotos (as well as Graves). It looks like I’m edging towards having an under active thyroid so I’ll look at that further next time I feel that I’m grinding to a halt!

[FlipperTD]

My wife's TSH was 80 [yes, 80] when she was diagnosed as hypothyroid, and her free T4 was just about unmeasurable. She was very ill, but the magic little Thyroxine tablets sorted her out although it took months for her to recover. Given that these tend to be part of the auto-immune family, then it's more a matter of waiting to see what happens next, and getting some treatment. Her TSH now runs about 0.1 - 0.2 and T4 around 20, and she's well.

Good luck.

[JanD236 in reply to FlipperTD]

That’s great, I’m glad to hear your wife is well after being so very hypo.

I was warned by the endo treating my Graves that I’m likely to end up hypo and my GP let’s me have annual blood tests to check.

[FlipperTD]

After many years of Haematology, I learned a lot about thyroid in a short space of time, and was alarmed at the incidence of the conditions. So far, I've swerved it, but my father was another hypothyroid. Thanks for your good wishes. Annual checks are the way.