J Clin Pathol Qual Control.  1997 Dec;19(2):281-287.

A Study on the Verification for Modified Westergren Erythrocyte Sedimentation Rate and Acceptability of Undiluted Method

• Kim HK
• Yong DE
• Park Q
• Song KS

Abstract

BACKGROUND: Erythrocyte sedimentation rate (ESR) is one of the oldest laboratory tests, but it is still frequently ordered by physicians. Because the Westergren method recommended by ICSH (International Committee for Standardization in Haematology) is cumbersome and labor-intensive, and daily quality control of the procedure is difficult to perform, many laboratories have used a variety of modified methods. Therefore, we attempted to verify our laboratory's current modified Westergren method for quality assurance and to determine the acceptability of a simpler undilution technique based on Westergren's method.
METHODS
To verify our routine procedure, we chose 43 EDTA blood specimens with hematocrit of 0.35 or less. The tests were performed by our routine, modified Westergren method and ICSH standardized method simultaneously, and the results were plotted along with the 95% action limits. To evaluate the acceptability of the undilution technique, we compared ESR results by dilution and undilution techniques, using 60 specimens with wide ranges of hematocrit.
RESULTS
All the test results for verification of our routine ESR method fell within the allowable limits proposed by ICSH. The undiluted method showed acceptable correlation with the diluted method (r=0.91), but generally the results were higher than those using the diluted method, regardless of the hematocrit levels. And following conversion derived from the regression formula, 4 of the 60 test results using the undiluted method showed disagreement with thoses of the routine dilution technique in the judgment of normal and abnormal.
CONCLUSIONS
The currently-used dilution technique of the modified Westergren ESR is reliable and it apprears that the use of the undiluted method applied to the Westergren tube should be avoided as a routine laboratory technique.

MeSH Terms

Blood Sedimentation*
Edetic Acid
Erythrocytes*
Hematocrit
Indicator Dilution Techniques
Judgment
Quality Control
Edetic Acid