Sedimentation Rate (Sed Rate) or Erythrocyte Sedimentation Rate
(ESR)

Sample type

1. Obtain an EDTA-anticoagulated venous sample of 5 mL or 3.8% sodium citrate.

Use

Sedimentation occurs when the erythrocytes clump or aggregate together in a column-like manner (rouleaux formation). These changes are related to alterations in the plasma proteins. Normally, erythrocytes settle slowly because normal RBCs do not form rouleaux.

Precautions

Explain test purpose and procedure. Obtain appropriate medication history. Fasting is not necessary, but a fatty meal can cause plasma alterations.

Suction the specimen into a graduated sedimentation tube and allow to settle for exactly 1 hour. The amount of settling is the patient’s ESR.

Interfering factors

1. Allowing the blood sample to stand >24 hours before the test is started causes the ESR to decrease.

2. In refrigerated blood, the ESR is increased. Refrigerated blood should be allowed to return to room temperature before the test is performed.

3. Factors leading to an increased ESR include:

   a. The presence of fibrinogen, globulins, C-reactive protein, high cholesterol b. Pregnancy after 12 weeks until about the fourth postpartum week

   c. Young children

   d. Menstruation

   e. Certain drugs (eg, heparin, oral contraceptives)

   f. Anemia (low Hct) g. Macrocytosis

4. The ESR may be very high (up to 60 mm/h) in apparently healthy women aged 70 to 89 years.

5. Factors leading to reduced ESR include:

   a. High blood sugar, high albumin level, high phospholipids

   b. Decreased fibrinogen level in the blood in newborns, hypofibrinogenemia

   c. Certain drugs (eg, steroids, high-dose aspirin)

   d. High Hb and RBC—polycythemia

   e. High WBC

   f. Abnormal RBCs (eg, sickle cells, spherocytes, microcytosis)

Pre analytical errors

1- Incorrect Analysis ordered

2- patents identification error

3- sample collection errors

Corrective action

1- Using appropriate technology.

2- Monitoring quality indicators in the lab.

3- Choosing appropriate products.

Post analytical errors

1- Report delayed

2- incorrect interpretation

3- Sharing the results of patients or writing the result incorrectly.

Corrective action

1- Done Accurate Reports after doing tests

2- Assure that the prescribed preventive maintenance for the instruments is performed

3- Attention when delivered the results of patient and write them in the reports

Reference Range

Men: 0–15 mm/h (over age 50 years: 0–20 mm/h)

Women: 0–20 mm/h (over age 50 years: 0–30 mm/h)

Children: 0-10 mm/h