Frequently Asked Questions
I have read some old papers indicating that the 1 hour reading time of the ESR can be greatly reduced by fixing the tube at an angle of 60 or
45 degrees instead of upright. Does this give accurate results?
Can I use EDTA anticoagulated blood to perform the ESR test?
When filling the Dispette 2 system, if the blood reaches the zero mark at the top before the other end of the Dispette gets to the bottom of
the filling reservoir should I stop pushing and just set up the test in the stand as it is?
Can the micro method give the same accuracy as the full Westergren method?
Are manual ESR tests CLIA-waived?
Is it necessary to run controls on manual ESR tests?
What temperature range should ESR's be performed at?
What is the storage temperature for the Dispette 2?
Is the Dispette 2 ESR system self-zeroing or graduated?
What method should we use for ESR testing?
How can I obtain a copy of the CLSI Procedures for the Erythrocyte Sedimentation Rate Test; Approved Standard - Fifth Edition?
What should I do if our facility fails the proficiency test?
Do Guest Scientific ESR systems conform to CLSI Standards?
Does anemia affect ESR results?
What buffered sodium citrate tube should I use?
Q: I have read some old papers indicating that the 1 hour reading time of the ESR can be greatly reduced by fixing the tube at an angle of 60 or
45 degrees instead of upright. Does this give accurate results?
A: No, the ESR tube (Dispette™) must always be perfectly vertical as measured by a spirit bubble or plumb line. The papers in favor of the idea written in
the mid 1930's and early 1940's were shown to be faulty by several workers and finally discredited in 1967 (Lemtis and Schoetensack). The I.C.S.H. continues
to recommend that the tube "should be held vertical (confirmed by a plumb line or equally effective device)"
Q: Can I use EDTA anticoagulated blood to perform the ESR test?
A: Yes, but if you are performing the Westergren method test as do most people today, you still need to make the one in five dilution (i.e. four parts blood
added to one part diluent) that was used with the original technique because only liquid citrate was available at that time as an anticoagulant. The diluent
you use can be normal saline or trisodium citrate at a concentration of between 0.10 to 0.136 mol/litre. - see I.C.S.H. recommendations, Journal of Clinical
Pathology, 1993: 46: 198 - 203.
Q: When filling the Dispette 2 system, if the blood reaches the zero mark at the top before the other end of the Dispette gets to
the bottom of the filling reservoir should I stop pushing and just set up the test in the stand as it is?
A: No, otherwise the red cells will fall into the space between the bottom of the Dispette and the filling reservoir and hence give inaccurate results.
The overflow chamber above the zero mark on the Dispette is designed to take the excess blood that will result from pushing right to the bottom.
Q: Can the micro method give the same accuracy as the full Westergren method?
A: No, although some workers have shown good correlation between the two methods in ESRs giving normal to slightly raised values (Barret & Hill, Journal of
Clinical Pathology, 1980; vol. 33, 1118 - 1120). But the higher the ESR the greater is likely to be the variation between the results given by the two methods.
Never-the-less this means that the Micro-Dispette can be a very useful screening method or an indicator of normal or raised ESR values where it is difficult to
obtain a larger volume of blood sample.
Q: Are manual ESR tests CLIA-waived?
A: Yes. Please visit this website for more details.
Q: Is it necessary to run controls on manual ESR tests?
A: ESR tests are CLIA-waived and are exempt from the Federal oversight to the extent described at the FDA's website. CLIA's position on QC testing can be found at http://www.cms.gov/CLIA/downloads/qchigh.pdf.
Procedures for the Erythrocyte Sedimentation Rate Test; Approved Standard – Fifth Edition, CLSI-H02-A5 does not stipulate the extent or frequency of QC testing required. However, it discusses how laboratory technique issues can influence ESR results and provides guidance for QC activities.
Q: What temperature range should ESR's be performed at?
A: ESR tests should be performed at temperatures between 64 to 77°F (18 to 25°C).
Q: What is the storage temperature for the Dispette 2?
A: The Dispette 2 should be stored in a cool, dry place at 50 to 75°F (10 to 24°C). Never freeze the Dispette 2.
Q: Is the Dispette 2 ESR system self-zeroing or graduated?
A: The Dispette 2 is self-zeroing; when you push the Dispette to the bottom of the reservoir any excess blood sample is absorbed by the cotton plug in the overflow chamber at the top, formed by the two blue grommets.
Q: What method should we use for ESR testing?
A: Laboratories should follow the CLSI published, "Procedures for the Erythrocyte Sedimentation Rate Test, Approved Standard – Fifth edition, CLSI-H02-A5."
Q: How can I obtain a copy of the CLSI Procedures for the Erythrocyte Sedimentation Rate Test; Approved Standard – Fifth Edition?
A: Please visit www.techstreet.com for information on how to purchase Procedures for the Erythrocyte Sedimentation Rate Test; Approved Standard – Fifth Edition, CLSI-H02-A5.
Q: What should I do if our facility fails the proficiency test?
A: The most common causes of erroneous ESR results are from environmental variables and lab personnel training issues.
For the lab environment; verify the laboratory conditions and the setting of the testing location. These considerations are covered under the "PRECAUTIONS" section of the product labeling. Pay particular attention to any new equipment introduced into the laboratory near the ESR testing vicinity that might cause vibration and/or temperature fluctuations.
For lab personnel training; check that lab personnel are performing the test correctly by reading the ESR test at exactly 1 hour. Premature and late ESR readings are a common cause of ESR erroneous results. These mistimed readings can have drastic effects on the reported ESR result. Consult the "PRECAUTIONS" section of the product labeling for more information.
Q: Do Guest Scientific ESR systems conform to CLSI Standards?
A: Yes, the Dispette, Dispette 2, SedPac and Vacupette as well as the 5-place ESR stand are designed to meet the International Congress for Standardization in Hematology (ICSH) and the Clinical Laboratory Standards Institute (CLSI) Standards.
Q: Does anemia affect ESR results?
A: Yes, anemia will cause a raised ESR. Consequently, the ESR alone should not be taken as indicative of a particular disorder being present or absent. Anemia, by altering the ratio of red cells to plasma, encourages rouleaux formation and accelerates sedimentation in the lag phase. Cellular factors in anemia may also affect the rate. For example, in iron-deficiency anemia, a reduction in the intrinsic ability of the red blood cells to sediment may compensate for the accelerating effect of an increased proportion of plasma. In addition, you may see a higher rate in blood loss anemia due to the lower number of red cells.
Q: What buffered sodium citrate tube should I use?
A: The ICSH recommends that the trisodium citrate should be "within the range 0.10 to 0.136 mol/L."
