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ESR and CRP Tests

Am a bit confused about the numbers given for these tests as what forum members give for these tests do not resonate with what I was told by my GP.

At time of diagnosis, I was told the ESR was 1.97, when it should be less than 1.72, and CRP was 39, when. It should be less than 11. Are there two ways of measuring these tests?

A subsequent blood test, after 2 weeks of preds gave ESR of 1.68, and CRP of less than 3, which was good.

Can anyone clarify for me please?

Many thanks

11 Replies

Well, as you say there seem to be different ways of measuring ESR and CRP. Mine, on the NHS, say that the normal range for ESR is less than 12 and for CRP less than 5. MY ESR has been between 6 and currently 36 and CRP has never been in the normal range: between 11 and currently 24. My numbers are high for me at the moment . I am not flaring, but I think it is because I have had several bacterial infections recently, which reminds us not to rely totally on the numbers because they only show that there is inflammation, not what is causing it.


Looking at the figures you've quoted I'd think at first sight you have them the wrong way round.

However, the more likely answer is that it isn't sed rate/ESR that was measured but plasma viscosity where the normal range is 1.50-1.72

That then leaves us with the CRP figure you quote which doesn't make sense to me either because the numbers don't fit anything - CRP should be below 1 or 10 depending on what units are being used: mg/dL (100ml) or mg/litre, a difference of a factor of 10

Did you mistype the 11 maybe?

For Sed rate/ESR the Mayo says "Results from your sed rate test will be reported in the distance in millimeters (mm) red blood cells have descended in one hour (hr). The normal range is 0-22 mm/hr for men and 0-29 mm/hr for women."


Hm! Yes, I think your explanation on plasma viscosity makes sense, and the test results would certainly indicate this.

As for the CRP, no I didn't mistype this, though I easily could have done. I wrote it all down very carefully at the time,but are the results really so far out as to make no sense at all. I clearly remember the GP saying the results were high, which was why she started me at 30mg.

Anyway, thank you as ever for your helpful reply, which I really appreciate.



just to add more confusion to the plot, who ever said this illness was easy? somewhere along the line I was told/have read that the following figures should apply:

ESR - your age +10 divided by 2. in my case 68+10 = 78/2 = 39. Although somewhere else I read it should be less than 20!

CRP: less than 6

No wonder my GP says "don't go by the figures, take notice of how you feel!" Not very scientific, but maybe he has a point.

Keep smiling, it's a lovely sunny day here in deepest Dorset, and too much like hard work to trouble the old brainbox too much.


The "calculation" was derived some years ago because they thought it was "normal" for ESR to increase with age and for it to be higher in women than men because that was what they saw in the general population who were apparently healthy. In fact it is far more likely that older people with a raised ESR have some unidentified inflammation going on - it is a totally non-specific test anyway. And the top age for the equation was 55 by the way so anything over 30 is getting iffy!

At birth your ESR is zero and rises slowly through childhood. The more recent guidelines are for 20 to be the top end of "normal" and should be putting a whole new threshold for diagnosing PMR or any other inflammation - IN ASSOCIATION WITH SYMPTOMS. But really the symptoms should ALWAYS be king - my ESR has never been above 7 even when I couldn't move and is normally about 4.


No wonder we mere mortals get confused!


Thanks DorsetLady - I like that one! Yes, how you feel is surely the best measurement yardstick, especially when you realise you can still have pain even when test figures show good results.

Am taking a rest now having been ringing bells for a. Local wedding, then hopefully doing a bit of gardening in the sun.

Good luck.


My CRP started at 123. It is now down to 5, so it is quite possible yours was 39.

I have been lying in the garden and planning my gardening activities. Much easier. There was a very noisy thrush banging snails on the ground, so when you walk up the path there is a loud crunching sound underfoot.


The ESR will always be a whole number- never with a decimal place. The age+10/2 is now considered out of date. Just like most of my medical knowledge these days. I was told that in 10 years 50% of what you were taught will be redundant. The only problem is knowing which 50%!

I went to the Casculitis symposium yesterday. It was fabulous.


Ooh, Saxjody, I was there too, as were Keyes and Runrig. It was so lovely to meet them for the first time (Runrig found me, Heaven knows how!) and I would love to have met you too. How wonderful for the symposium to set one day aside specially for us patients - and how very informative too.


Whoops Vaculitis


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