ERYTHROCYTE SEDIMENTATION RATE

Effective Date: 
Mon, 10/28/2013
Reviewed: 
Tue, 01/10/2017
Policy: 
Principle:

The erythrocyte  sedimentation rate (ESR)  is a  nonspecific measurement used to detect and monitor an  inflammatory response to tissue  injury.  lt denotes the  presence of disease but not its severity.  The ESR is affected by three factors:   erythrocytes, plasma concentration,  and mechanical /technical factors.   ln  normal  blood,  the red  blood cells remain  more or less separated by being negatively charged.  ln certain diseases, this negative change is  reduced causing the  consequent formation of rouleaux.  These larger masses of red blood  cells have  a faster rate of fall (increased  ESR).  Anisocytosis and poikilocytosis reduce the ability of the erythrocytes to form  aggregates, and  the ESR is subsequently falsely low.  In severe  anemia, the ESR is markedly elevated.  Increased albumin will tend to  lower the ESR.  lt is important that the ESR tube  be exactly perpendicular. The ESR may be used to follow the progress of certain diseases such as tuberculosis  and  rheumatoid  arthritis.  The ESR is  increased  in  pregnancy, acute and chronic infections,  menstruation,  hypo- and hyperthyroidism,  and  acute hepatitis.  A decreased ESR will be present in polycythemia,  congestive heart failure,  and  in  the presence of red blood cell abnormalities.

Methods:

Modified Westergren

Materials:
  • Streck ESR vacuum tubes
  • Streck ESR-10 Manual Rack
  • Disposable plastic  pipets
  • ESR-Chex Assayed Hematology Controls
  • Calibrated Timer
Quality Control:

Run 2 levels of ESR-Chex on each day ESR patient testing is performed. (Note: If no patient in-house ESR is ordered, no need to run QC)

Record QC results in Harvest Orchard LIS

Procedure: 

 

  1. Collect blood  in  EDTA-lavender top vacutainer tube.
  2. Withdraw blood from lavender-top tube  using disposable plastic pipet, and fill vacuum tube to fill line indicated on label.
  3. Replace stopper and mix by thoroughly inverting 6-8 times.  Place tube  in upright position  in the ESR-10 rack with the menicus of the blood-air interface level with the zero measurement on the rack.
  4. Insure that the bubble on the ESR-10 rack is centered, indicating rack is on level surface. Adjust rack if needed.
  5. Set timer for 30 minutes.
  6. Read ESR making sure that your eyes on the same horizontal level as the rack since reading at an angle will result in error.

 

 

 

Key Points: 

Normals:

Men 0-21  mm/hr
Women 0-28 mm/hr

Limitations:

  1. If the concentration of EDTA is greater than  recommended,  the ESR will  be falsely decreased,  (blood volume is  less than  2.5  ml  in a 5 ml tube).
  2. If the ESR stands for more than 30  minutes, the ESR will  be falsely elevated.  lf the test is timed for less  than 30  minutes, the value obtained is too low.
  3. A marked increase (or decrease) in the room temperature leads to  increased  (or decreased) ESR results.
  4. Tilting of the ESR tube  increases the sedimentation  rate.
  5. Bubbles in the  blood  cause invalid results.
  6. Fibrin clots present in the  blood validate test results.
  7. The ESR should  be set up within 2 hours of blood collection, or within 6 hours, if specimen drawn  into EDTA tube and refrigerated.

 

References:

Streck ESR vacuum tubes package insert #350438  Rev 2012

Streck ESR-10 Manual Rack package insert #350507-3  Rev 2012

Erythrocyte sedimentation rate (ESR) measured by the Streck ESR-Auto Plus. Vennapusa B, De La Cruz L, Shah H, Michalski V, Zhang QY. Am J Clin Pathol. 2011 Mar;135(3):386-90

Brown,  B.A.,  Hematology:  Principles and  Procedures,  Sixth Edition, 1993,  Lea  and Febiger,  Philadelphia,  pp.  107-111.