CRP vs hs-CRP
- Thread starter Jaybee00
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Kitty
Senior Member (Voting Rights)
I've only heard of it used to assess risk—a friend was tested because of a family history of heart disease.
Jonathan Edwards
Senior Member (Voting Rights)
It is just an artefact of normal ranges. Normal range for CRP is often given as <X because the assay is not sensitive enough to cover the edge of the 2SD part of the Gaussian. A highly sensitive assay can pick that out.
But using Gaussian ranges for these things is a nonsense anyway and in particular for CRP because people vary up to 10-fold in their CRP baseline and response maximum. Even where there isn't this variation a Gauss-defined 'normal range' is biologically invlid.
Take serum urate. The level of serum urate at which crystals can form and produce gout is within the 2SD range. So people get told they do not have gout because the lab says the result is 'normal'. Barmy.
There are all sorts of thing that affect CRP so something below 2mg/deciL (20mg/L) might mean something but probably doesn't.
But using Gaussian ranges for these things is a nonsense anyway and in particular for CRP because people vary up to 10-fold in their CRP baseline and response maximum. Even where there isn't this variation a Gauss-defined 'normal range' is biologically invlid.
Take serum urate. The level of serum urate at which crystals can form and produce gout is within the 2SD range. So people get told they do not have gout because the lab says the result is 'normal'. Barmy.
There are all sorts of thing that affect CRP so something below 2mg/deciL (20mg/L) might mean something but probably doesn't.
Peter T
Senior Member (Voting Rights)
In case any others like me struggle with acronyms a quick web search came up with:
CRP or C Reactive Protein is a protein produce in the liver indicative of inflammation in the body identified by blood test, hs-CRP is a high sensitive blood test that can identify low levels of CRP in the blood.
CRP or C Reactive Protein is a protein produce in the liver indicative of inflammation in the body identified by blood test, hs-CRP is a high sensitive blood test that can identify low levels of CRP in the blood.
OK—since this answer is more than 2 SD above my IQ level, all things being equal—which is worse—to have low CRP and High hs CRP or high CRP and low hs CRP (is the latter even possible)?
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Jonathan Edwards
Senior Member (Voting Rights)
The latter should not be possible.
hsCRP is just a higher spec assay for the same thing.
So a very high CRP suggestive of sepsis would be 600mg/L.
On hsCRP it will be either 600mg/L or >limit of assay.
A high CRP is 200mg/L.
A slightly raised CRP worth looking for possible causes in an otherwise fit person would be 50mg/L.
A CRP of 10mg/L does not warrant investigation. On hs CRP it would be 10mg/L.
But a lot of people will have a CRP level. of 3mg/L, which on CRP assay is often reported as <10mg/L or below limit of assay. The hs CRP will pick it up as 3mg/L.
hsCRP becomes relevant if you are wanting to assess long term cardiac risk because people with vascular disease more often have a CRP above 3mg/L than others.