ESR affected by:

  • Gender

  • age

  • pregnancy

  • Temperature

  • Drugs (steroids, asalicylates)

  • smoking

Severity and CRP:

10-40: mild inflammation, viral or bacterial infection

40-100: moderate inflammation viral or bacterial

100-200 marked inflammation, bacterial

>200: severe bacterial infection, vasculitis, severe arthritis

Infection

  • CRP may be useful when considering undifferentiated infection

  • if >100 then likelihood of bacterial infection greater compared to viral infection

Screening

  • Neither CRP or ESR useful

Polymyalgia rheumatica

  • both CRP and ESR recommended

  • CRP reommended for monitoring

Giant cell arteritis

  • Cases with normal ESR and increase CRP reported

  • higher sensitivity for diagnosis

  • CRP monitoring

Rheumatoid arthritis

  • neither CRP nor ESR included in diagnostic criteria

  • CRP for monitoring

Systemic lupus erythematosus

  • lack of correlation between CRP and disease activity

  • distinguish between lupus flare and infection

    • normal in flare

    • increase in infection

    • ESR elevated in both

Malignancy

  • no role

Differentiate between bacterial and viral pneumonia

  • insufficient evidence

  • van der Meer et al.

    • systematic reveiw

    • poor quality

    • not sensitive nor specific to rule in infiltrate and bacterial aetiology

    • not enough high quality studies so cannot be sure

      • van der Meer V, Neven AK, van den Broek PJ et al. Diagnostic value of C reactive protein in infections of the lower respiratory tract: Systematic review. BMJ 2005;331:26-9.

HsCRP and CVRA

  • CRP is consistently, although weakly, associated with CVD

  • does’t add enough to recommend routine adoption for populaiton screening