Aspect Hazy

The automatic reading of the Westergren sedimentation pipettes is performed by moving an optical sensor along the pipettes. While the sensor is moving, it is taking a reading every 0.25 mm. The sensor is reading the absorption of infrared light through the Westergren pipette filled with blood. From these readings, values at a number of absorption levels are determined. All absorption figures are relative to the darkest and lightest reading (darkest = 100 % and the lightest = 0 % absorption respectively).

By definition the levels are:

Graphic showing typical absorption values of a sample

Although the result of the ESR measurement is expressed in a quantifiable unit ("mm"), it is not a measurement that involves measurable quantities of any analytes or substances. What is measured is the result of a physiological process that is influenced by the properties of the blood sample and external factors. The ESR measurement must therefore be regarded as a qualitative process.

The 'sedimentation' value is the distance in millimeters between the cells/plasma level (87.5% absorption) and the meniscus. If there is no haze, the absorption drops quickly to a value below the 75% level. If the distance between the 87.5% and the 75% level is less then 3mm, the report will state 'CLEAR'. If the distance between 87.5% and 75% level is more than 3mm then the report will state 'HAZY'.

Hazy reports are shown when the change from the hazy level to the cell/plasma separation level occurs outside the given distance. The following code messages are reported/printed in column 5.

The following 4 codes are defined:

Results with hazy aspect can be suppressed in the menuLimit error settings.

Depending on the length of the 'hazy' area, three classes of 'haziness' are reported: