Value of ESR CRP

[bananas85]

I realize this values are pretty non specific specially in elderly if elevated,

however if normal value, can you rule out major infections in immuno competent host such as endocarditis, abscesses, diskitis, hidden osteo etc.

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[Raryn]

Normal helps rule out a lot of the chronic inflammatory conditions, yes. Abnormal is pretty much never that useful, though if I have a suspicion of osteo and the ESR comes back >70, it makes me more likely to get the MRI.

 

[IM2GI]

Check out procalcitonin if you are looking for a more specific marker of bacterial infection. It is most validated in the ICU/sepsis population, but is very specific for bacterial infection.

If you are looking for bowel inflammation (i.e.: IBD), fecal calprotectin is bowel specific marker of inflammation.

 

[Escape from Detroit]

Here's some numbers on ESR for diabetic foot osteomyelitis:

http://www.ncbi.nlm.nih.gov/pubmed/8872749
http://www.ncbi.nlm.nih.gov/pubmed/16759307

Sensitivity >90%. The studies didn't really calculate specificity. So you should be able to rule out infection unless there's positive cultures or something concrete

 

[Bostonredsox]

Check out procalcitonin if you are looking for a more specific marker of bacterial infection. It is most validated in the ICU/sepsis population, but is very specific for bacterial infection.

If you are looking for bowel inflammation (i.e.: IBD), fecal calprotectin is bowel specific marker of inflammation.

There is data showing equivalence in crp and pro calcitonin in the setting of possible sepsis and crp is 1/50th the cost.

 

[jdh71]

I usually don't use either in practice unless I'm working up an ILD I'm suspicious of having an underlying rheumatological etiology.

I do think it's nice to see them trending DOWN in a patient that one of my consultants is ordering the lab on.

 

[drfunktacular]

In rheum they can be useful for monitoring the progress of a disease... IF one or both is elevated to begin with, AND IF it trends down with treatment and clinical improvement

When it comes to diagnosis of rheumatic disorders the classic case is GCA/PMR, in which case elevated ESR is highly suggestive in the appropriate clinical setting. Otherwise they are not that useful for diagnosis of rheumatic disorders. SLE in particular can be raging with a normal ESR/CRP... in fact some rheumatologists feel that an elevated ESR in a hospitalized SLE patient indicates that something else like infection is going on and not SLE activity.

Bottom line is they should be interpreted with caution, in light of the rest of the clinical situation and results, just like every other lab result

 

[zeloc]

They can be very useful in the right context. Eg, if someone has a CRP > 200, how many things can cause that? A serious bacterial infection, temporal arteritis, etc. Another example - I once had a patient that looked well and all the tests were coming back normal except inflammatory markers were sky high. It indicated that there was something abnormal and additional looking was necessary.
As others have pointed out, good to rule out chronic inflammatory conditions of various organ systems. Also you can look at the trend. If it elevated in an elderly person but you see a big deviation, then the difference could be important.
Let's not forget hsCRP which is the same test just fractionated more.

 

[jsman25]

"Elevated ESR and CRP mean one thing. The lab is open"
~anonymous AM report attending