LifeLabs New Combined Cytology and HPV Requisition
The erythrocyte sedimentation rate (ESR) is widely used as an indicator of inflammation. The traditional Westergren method measures the rate at which red cells sediment in plasma over one hour, and the results are influenced by the overall charge (or zeta potential) of the red cells. The net negative charge on red cells causes them to resist each other, while the net positive charge of serum proteins encourages adhesion causing a faster rate of sedimentation and therefore a higher ESR (i.e., during inflammation and often due to fibrinogen).
Although easy to perform and inexpensive, the Westergren method takes at least 30 minutes to perform in the laboratory. The method is imprecise and its specificity can be reduced by several factors unrelated to the inflammatory process, often making the results unreliable and imprecise.
LifeLabs recently introduced ESR testing by a new methodology that is faster and easier to perform. The new method analyzes the aggregation capacity (or zeta potential) of the red cells using optical density and has reduced analysis time to 20 seconds (more details available on request). Moreover, this new technology eliminates the interferences often encountered by Westergren method and has been proven in studies to better correlate with inflammation when compared to that method.
In April 2013, LifeLabs introduced this new methodology for ESR analysis. Reference interval changes were implemented at that time and interpretive message attached to all reports. This message will remain in the patient reports for 6 months.