CRP ESR - okcvideo.com

Sed rate and CRP

Erythrocyte sedimentation rate (Sed rate, ESR) and C reactive protein (CRP) are tools to measure inflammation. They are used in infectious, autoimmune disease but can also be elevated in malignancy and spuriously for other medical reasons.

Spurious = not being what it purports to be; false or fake.: "separating authentic and spurious claims".

The classic inflammatory disease associated with ESR and CRP is giant cell arteritis.

Giant cell arteritis = vasculitis involving cranial arteries.

Normal ESR elevates with age but in general normal range is 0 to 20 mm per hour. Note the unit is different than in most tests. It is a distance over time. That is because ESR is measured by measuring the amount of time it takes for a red blood cell to migrate from the top to bottom of a capillary tube.

From C Eustice. Erythrocyte Sedimentation Rate (Sed Rate) Overview. VeryWell Health

This explanation is from the Cleveland Clinic website.

The blood is placed into a tall thin tube and the test measures the rate of fall (sedimentation) of erythrocytes (red blood cells). The red cells settle faster than normally if there is alteration of blood proteins, which indicates inflammation.[1]

The average ESR in giant cell arteritis is 70.

Disease

Avg ESR (mm/hr)

Avg CRP (mg/L)

Giant cell arteritis

Polymyalgia rheumatica

Rheumatoid arthritis

Cancer, severe infection, vasculitis

>100

ESR CRP in RA

% active RA patients

ESR

CRP

Elevated

Normal

Elevated

Normal

Questions: Is there a known range of sed rate and CRP in the population? Does obesity or other factors besides disease affect a "normal" sed and CRP? If treatment with steroid reduces ESR CRP, does that prove a patient has inflammatory disease?

CRP

CRP reacts quicker than ESR. So, if wanting to measure response to a treatment in days rather than weeks, CRP might work better than ESR.

ESR and CRP will typically correlate and be close to equal but in general the CRP is lower than ESR. So, a typical active RA patient ESR = 40 and CRP=30. So, ¾ is the right adjustment or equilabrator.