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?

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.