Overview: Erythrocyte Sedimentation Rate (ESR) Test
Introduction: The Erythrocyte Sedimentation Rate (ESR) Test measures the rate at which red blood cells settle in a tube to detect inflammation or infection, causing fever or joint pain. Following 2023 ACR guidelines, it uses a sedimentation assay for reliable results, aiding in inflammatory screening. This test is critical for guiding diagnosis, treatment, and improving outcomes in hematology for patients with suspected inflammatory or infectious conditions.

Other Names: ESR Assay, Sed Rate Test.

FDA Status: Laboratory-developed test (LDT), meeting hematology standards for diagnostic accuracy.

Historical Milestone: ESR testing began in the 1920s with inflammation research. Standardized sedimentation methods emerged in the 1970s, and by the 2000s, automated assays improved precision.

Purpose: Detects inflammation or infection, guides treatment, and monitors ESR in patients with fever or joint pain.

Test Parameters: 1. Erythrocyte Sedimentation Rate

Pretest Condition: No fasting required. Collect whole blood at any time. Report symptoms like fever or joint pain, and list medications like anti-inflammatories.

Specimen: 2-5 mL whole blood (EDTA). Transport in a biohazard bag within 8 hours.

Sample Stability at Room Temperature: 8 hours

Sample Stability at Refrigeration: 7 days

Sample Stability at Frozen: 6 months

Medical History: Document fever, joint pain, or history of inflammatory/infectious conditions (e.g., arthritis, infection). Include current medications, especially anti-inflammatories.

Consent: Written consent required, detailing the tests purpose, diagnostic implications, and potential need for anti-inflammatory or antimicrobial therapy.

Procedural Considerations: Uses a sedimentation assay (e.g., Westergren method) to measure ESR. Results are available in 1-2 days, enabling rapid clinical decisions.

Factors Affecting Result Accuracy: Hemolysis, improper storage, or medications can affect results. Non-inflammatory conditions may elevate ESR.

Clinical Significance: Elevated ESR suggests inflammation or infection, prompting further testing or treatment. Normal ESR may require additional inflammatory markers.

Specialist Consultation: Consult a rheumatologist or infectious disease specialist for result interpretation.

Additional Supporting Tests: C-reactive protein (CRP), complete blood count, or imaging to confirm inflammation or infection.

Test Limitations: Non-specific elevations may occur in non-inflammatory conditions. Results require clinical correlation.

References: ACR Inflammation Guidelines, 2023; Arthritis & Rheumatology, Crowson CS, 2022.