Most commonly used technique to measure the ESR
Is the nonautomated, 60-minute Westergren method the most commonly used technique to measure the ESR?
No. Surveys reveal that roughly two-thirds of laboratories across the globe use either modified automated measurements based on the Westergren method or alternative novel methods. Techniques based on the Westergren method utilize specialized vacuum tubes that can be filled without the need for transfer by a technician. Many of these instruments use infrared light to measure the final length of sedimentation, with results measured at 15–30 minutes depending on the instrument and then extrapolated to Westergren (60 minute) values. Alternative novel methods of ESR measurement may use centrifugation or rapid acceleration of the blood sample followed by photometric rheology to measure rouleaux formation. This latter technique uses an infrared laser to track the RBC-plasma interface at several points during sedimentation and then transforms the data on established sedimentation curves from the Westergren method. Results can be available in as little as 20 seconds to 5 minutes with some instruments. Several studies have shown that results may differ between automated ESR measurements and the traditional Westergren test, especially at higher ESR values where automated values are often falsely lower. The influence of anemia, hyperfibrinogenemia, and other factors listed in Question #3 on methods utilizing photometric rheology is uncertain. The 2018 Medicare National Limit Amount cost for the test is $4.38 (nonautomated) or $3.33 (automated).