|
Overview :
The erythrocyte sedimentation rate (ESR) is affected by the
patient's hemoglobin and hematocrit levels as well as other factors (see
previous section). Pawlotsky et al developed the Sigma ESR which involves
adjusting the specimen hematocrit and summing readings taken at 4 times during
the first hour of sedimentation. Pawlotsky has since developed a simplified
version to increase acceptance of the approach.
Specimen collection:
(1) 5.2 mL
blood collected in a glass Seditainer tube (10.25 by 120 mm) anticoagulated with
lithium heparin.
(2) Blood
sample for hemoglobin and hematocrit measurement.
Parameters:
(1) measurement of sedimentation distances at 30 and 60
minutes
(2) hematocrit as a decimal fraction from 0 to 1
(3) hemoglobin in g/L
summed distance in mm =
= (distance at 30 minutes) + (distance at 60 minutes)
simplified sigma ESR =
= ((-0.005 * ((summed distance)^2)) + (2.542 * (summed
distance)) + (802.526 * (hematocrit)) - (0.92 * (hemoglobin)) - 164.701) / 2
Interpretation:
• The reference range is 17 to 53 mm in the first hour for
both genders and all ages.
• The upper limit of the reference range is affected by the
serum total cholesterol level.
|
Serum
Cholesterol |
Upper Limit of the Reference
Range |
|
<= 5.0
mmol/L |
50
mm/h |
|
5.01 -
6.00 |
54
mm/h |
|
6.01 -
6.50 |
59
mm/h |
|