The erythrocyte sedimentation rate (ESR) is a common hematology test that measures the distance red blood cells fall in a test tube in one hour. The specific container utilized for this blood analysis is typically a vacuum-sealed tube with a particular additive. The color coding associated with this specific tube indicates the presence of this additive, which is often an anticoagulant such as ethylenediaminetetraacetic acid (EDTA). For instance, a lavender-top or purple-top tube is routinely used for this procedure due to the EDTA inhibiting blood clotting and allowing for accurate measurement of the sedimentation rate. The color provides a visual identifier for laboratory personnel ensuring the correct collection vessel is selected.
Employing the correct collection method, including the appropriately colored tube, is crucial for the validity of the ESR results. Variations in additives, or the absence thereof, can impact the rate at which red blood cells aggregate and settle. Accurate ESR measurements are valuable in the diagnosis and monitoring of inflammatory conditions, infections, and some cancers. Historically, this test has been a simple yet informative tool for clinicians seeking to assess the presence and severity of systemic inflammation, although its use has evolved alongside more specific and sensitive inflammatory markers.
