Performing a Erythrocyte Sedimentation Rate Erythrocyte Sedimentation Rate
- Slides: 6
Performing a Erythrocyte Sedimentation Rate
Erythrocyte Sedimentation Rate • The erythrocyte sedimentation rate (ESR or sed rate) is a test measuring the rate at which erythrocytes (RBCs) settle. • This test is used to diagnose inflammation and inflammatory disorders. • The test is also used to monitor the treatment of an inflammatory disorder. • A sample of anticoagulated blood, commonly EDTA, is placed into a tube and the blood is allowed to settle. • After a specific amount of time, per the procedure used, the amount of RBC settling is measured.
Erythrocyte Sedimentation Rate • Performing an ESR — To perform a manual ESR test you need a calibrated tube filled with anticoagulated blood. — The RBCs will settle toward the bottom leaving plasma at the top area. —The sample is left for a specified amount of time. — At the end of the time period, you measure the distance from where the sample started to the settled RBCs. — Most healthy people have slow ESR rates. — In patients with specific inflammatory disorders, the rate of sedimentation is faster. — Sometimes the faster the settling the worse the severity of the disease.
Erythrocyte Sedimentation Rate • Factors effecting an ESR include…. . — The plasma’s properties if rouleaux is present ü Rouleaux is when the RBCs form stacks ü Rouleaux increases the mass of the RBCs and increases the rate of sedimentation. — The RBC’s properties ü Large RBCs (macrocytes) settle faster than small cells (microcytes). ü Irregular shaped cells cannot settle as fast and result in a slower rate of settling. ü Spherocytes (small compact cells) fall at a slower rate. ü The rate of settling is also affected by the number of RBCs present
Erythrocyte Sedimentation Rate • Factors effecting an ESR include…. . — Way the procedure is carried out ü The settling tube must be kept upright, straight, and standardized ü Counter should be level ü Temperature should be kept constant ü Blood sample should be used within 2 hours of collection and well mixed ü Test must be timed correctly • There are several methods used for performing an ESR. — Manual methods — Automated methods
Reference Ranges • Each method has its own reference values. • Reference values differ slightly depending on gender and age. • Most range from 0 -20 mm/hr