Erythrocyte Sedimentation Rate (ESR), vs C-Reactive Protein (CRP)

Erythrocyte Sedimentation Rate (ESR)

Sample

1. The whole blood sample is taken in the EDTA (anticoagulant). It measures the rate of sedimentation in one hour.
2. Or take blood in a 3.8% trisodium citrate solution.
3. The sample is stable for 2 hours at 25 °C and 12 hours at 4 °C.

Purpose of the test (Indications)

1. It can be done in occult diseases.
2. For the diagnosis of acute and chronic infections.
3. For collagen vascular diseases.
4. In advanced malignancies.
5. In tissue necrosis and infarction.
6. ESR can be used to monitor disease therapy, especially for autoimmune diseases. It will correlate with the severity of the disease or with the improvement in the disease course.
7. It is useful for the diagnosis and monitoring of temporal arteritis and polymyalgia rheumatica.
8. It is also used for monitoring Hodgkin’s lymphoma.

Pathophysiology

The definition of ESR:

1. 1. It Is the measure of RBCs settling in diluted plasma over a specified period of time.
   2. This is a numeric value in mm over a period of 60 minutes.

Principle of ESR: This is directly proportional to RBCs mass and inversely to plasma viscosity.

1. 1. The ESR is the rate at which RBCs settle out of anticoagulated blood in one hour.
   2. RBCs give rise to more rouleaux formation in abnormal conditions like inflammatory conditions and the necrotic process, resulting in aggregation of the RBCs, which make them heavier and more likely to fall rapidly so that there are increased RBCs mass, which increases the ESR due to faster settling of RBCs.
   3. There are two methods:
      1. Wintrobe method.
      2. Westergren method.
2. This is a nonspecific but not diagnostic test.
3. ESR is a measurement of the rate at which the RBC settles in saline solution or plasma over a specific time, usually one hour.
4. The ESR correlates with the plasma fibrinogen level and depends on the rouleaux formation of RBCs.
5. Factors affecting ESR:
   

   Factors affecting ESR

6. The inflammatory, neoplastic, infections, and necrotic diseases increase protein, mainly fibrinogen content of plasma, which leads to raised ESR levels.
7. ESR is advised in occult diseases.
8. Poikilocytosis, therefore, tends to inhibit sedimentation.
9. While increased flattening of RBC, as in obstructive liver disease, leads to accelerating sedimentation.
10. ESR should not be used to screen the asymptomatic patient for disease,
11. When ESR has been raised, a careful history and clinical examination will usually diagnose the disease.
12. This is a nonspecific test for diagnosing chronic diseases like Tuberculosis and raised in malignancies and autoimmune diseases.
13. Whenever any patient has raised ESR, he/she needs a thorough workup.
14. ESR is raised with aging and anemia.
15. Patients with >100 mm /hour ESR have a 90% predictive value  for serious diseases like:
    1. Malignancy, particularly myeloma.
    2. Infection.
    3. Collagen vascular disease.
    4. Rheumatoid Arthritis.
    5. Renal Disease.
    6. Sarcoidosis.
16. Raised ESR is seen in:
    1. Paraproteinemia.
       1. Multiple myelomas.
       2. Macroglobulinemia.
17. This test is useful for the diagnosis and monitoring of temporal arteritis and polymyalgia rheumatica.
    

    Factors affecting ESR

Affect of Anticoagulants on ESR:

1. Sodium citrate and EDTA do not affect the ESR.
2. Sodium or potassium oxalate shrinks the RBCs.
3. Heparin also causes shrinkage of the RBCs and gives rise to increased false ESR value.
4. So EDTA is the choice of anticoagulant.
   

   Anticoagulant effect on ESR

Limitations of ESR:

1. First of all, this is a nonspecific test.
2. Some time is not elevated in the active disease.
3. ESR may be influenced (increased) by other factors like pregnancy,  anemia, and a few other diseases.
4. Fibrinogen concentration.
5. Serum cholesterol level.
6. Globulin concentration, specifically gamma globulins.
7. Rouleaux formation decreases the surface area.
8. Sickle cells fail to form rouleaux formation, so there is low ESR.

Normal

• Male = 0 to 15 mm/hour.
• Female = 0 to 20 mm/hour.
• >50 years
  • Male = 0 to 20 mm/hour.
  • Female = 0 to 30 mm/hour.
• Child  = up to 10 mm/hour.
• Newborn  = 0 to 2 mm/hour.

Another source

• Men = 0 to 5 mm/hour.
• Women = 5 to 15 mm/hour.
• There is a progressive increase in old age.

There are conditions where ESR is not raised (normal ESR):

1. polycythemia vera (Erythrocytosis).
2. sickle cell anemia.
3. Hb C disease.
4. Spherocytosis.
5. Hypofibrinogenemia because of any reason.
6. Congestive heart failure.
7. Pyruvate kinase deficiency.
8. Anemia due to iron deficiency.
9. In case of acute allergy.

Falsely lowered ESR level seen in:

1. Sickle cell anemia.
2. Spherocytosis.
3. Hypofibrinogenemia.
4. Polycythemia.

Conditions leading to increased ESR value are:

1. Pregnancy after the 12 weeks of gestation.
2. Young children.
3. During the menstrual cycle.
4. Drugs like heparin, and oral contraceptives.
5. Anemia where the Hct is low.

Conditions where the ESR value is reduced:

1. High blood glucose (hyperglycemia).
2. In the case of raised phospholipids.
3. In the case of raised albumin.
4. In the case of raised WBCs.

ESR versus CRP (difference between Erythrocytes sedimentation rate vs C-reactive proteins):

Clinical parameters	ESR	CRP (C-reactive protein)
Normal level	Men = 0 to 5  Women = 5 to 15 mm/hour	<1.0 mg/dL
Sensitivity	Less sensitive	More sensitive
Pathophysiology (etiology)	Fibrinogen level goes up in the serum, which causes RBCs to clump	Dead and dying cells release chemical factors, which stimulate the liver to produce CRP
Increase in the level	No relation to antibody	Increases before the increase in the antibody level
Response to inflammation	Late response	Early response Appear within 24 to 48 hours The peak level is 48 hours Negative in 7 days Failure to become normal indicates tissue damage in the heart or elsewhere
After the inflammation	Take more time	Disappears early
Acute myocardial infarction	No relation	Increased Correlate with CK-MB Remains elevated for at least 3 months after AMI
Coronary anginal attack	No relation	Normal

• ESR is a nonspecific test, but this is one of the best tests to find any kind of abnormality in the body. Whenever you find raised ESR, never ignore it but have a thorough workup of the patients. It definitely shows some underlying disease.
  

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