Medical Analysis
Understanding Erythrocyte Sedimentation Rate (ESR) and Westergren Diagnostic Methods
The Erythrocyte Sedimentation Rate, commonly referred to as the ESR or sedimentation rate, is a vital haematology laboratory test. This procedure measures the rate at which red blood cells suspended in anticoagulated whole blood descend within a standardized glass or transparent plastic tube over a fixed period of one hour. As a routine clinical investigation, the ESR serves as a non-specific yet effective measure of inflammation within the body. Laboratory professionals determine the ESR primarily through the Westergren method, the Wintrobe Method, or by utilizing an automated ESR analyzer system.
Prognostic Value and Clinical Significance of ESR Monitoring
The ESR provides significant prognostic insight into various medical conditions. Most importantly, during a disease process, if serial ESR measurements demonstrate a consistent downward trend compared to previous values, it indicates that the patient is responding favorably to the prescribed treatment. Historically, before the widespread availability of modern, rapid diagnostic facilities, physicians routinely repeated the ESR test at intervals of 10 to 15 days to observe whether the rate was decreasing. A downward trend allowed clinicians to continue the current treatment regimen with confidence, a practice that was particularly essential in the management of Tuberculosis.
Indications for ESR Testing in Clinical Practice
Medical professionals order ESR testing for a variety of clinical scenarios to aid in diagnosis and monitoring. Common indications include:
Routine Health Screenings: Used as a baseline during general checkups.
Pre-operative Assessment: Performed as part of standard pre-surgical preparation.
Inflammatory Conditions: Utilized to assess systemic inflammation.
Pregnancy: Monitored as part of specific obstetric care.
Anaemia: Conducted to investigate underlying causes or complications.
Autoimmune Disorders: Essential for monitoring conditions such as Rheumatoid Arthritis, Lupus Erythematosus, Dermatomyositis, and Nephrotic Syndrome.
Infectious Diseases and Cardiac Health: Indicated for various acute or chronic infections and Congestive Heart Failure.
Technical Protocols: Sample Collection and Westergren Preparation
Accurate ESR results rely on standardized sample collection protocols. Professionals must use a light blue-capped tube containing 0.5 ml of 3.8% sodium citrate solution. Exactly 2 ml of blood is collected into this tube and mixed thoroughly with the anticoagulant. Following collection, the sample should be transported immediately to the laboratory or stored at a temperature between 2° and 8°. It is critical that the testing procedure begins as soon as possible, ideally within 2 hours of blood collection.
To prepare the 3.8% sodium citrate solution, lab technicians take 19 grams of trisodium citrate and dissolve it in 500 ml of distilled water, mixing thoroughly until the solution is fully prepared. The fundamental principle of the test is that red blood cells settle due to the force of gravity within anticoagulated blood. The rate of this sedimentation is directly proportional to the presence of plasma proteins such as fibrinogen and globulin. Furthermore, the formation of “Rouleaux”—stacks of red blood cells—significantly increases the speed of sedimentation. The final result is expressed in mm/hour.
Performing the Westergren Method and Equipment Standards
The Westergren tube is a straight glass or rigid transparent plastic tube, measuring 300 mm (30 cm) in length with a diameter of 2.55 mm, and is open at both ends. To perform the test, venous blood (usually 2 ml) mixed with sodium citrate (0.5 ml) in a 1.0 : 5.0 ratio is mixed well. The mixture is carefully drawn into the Westergren tube using a pipetting device or syringe up to the 0 mark. The filled tube is placed vertically in a specialized rack to ensure it remains in a stable, upright position. After leaving the tube undisturbed for exactly one hour at room temperature, the distance from the top of the red blood cell column to the top of the plasma is measured in millimeters. Notably, while sedimentation increases over time if blood is left standing, the ESR specifically records the rate of this process at the one-hour mark.
Normal Reference Ranges and Clinical Interpretations
| Age / Group | ESR (mm in 1 hr) |
| Children | 0-15 |
| Male | 0-15 |
| Female | 0-20 |
Clinical interpretations are categorized by whether the ESR is increased or reduced.
Increased ESR: Observed in pregnancy, anaemia, tuberculosis, chronic infections, Rheumatoid Arthritis, Lupus, various bacterial/fungal/viral infections, specific kidney diseases, and cancers like lymphoma or multiple myeloma.
Reduced ESR: Associated with polycythemia, hyperviscosity syndrome, sickle cell anaemia, leukemia, chronic fatigue syndrome, low plasma protein, and Congestive Cardiac Failure (CCF).
Prognostic Significance and Disease Monitoring
| Condition | Prognostic Utility | Interpretation |
| Rheumatoid Arthritis (RA) | Reflects disease activity & therapy response | ↑ ESR active disease, poor prognosis |
| Systemic Lupus Erythematosus (SLE) | Adjunct to CRP for flare assessment | ↑ ESR → possible flare, ↑ disease activity |
| Temporal Arteritis (GCA) | Diagnostic & therapeutic monitoring | ↓ESR post-steroids → good response; ↑→ relapse |
| Polymyalgia Rheumatica (PMR) | Tracks inflammatory control | Normalizing ESR → remission; persistent ↑→ active disease |
| Chronic Infections (TB, Osteomyelitis) | Indicates infection severity & chronicity | Persistent ↑ ESR → poor control, deep focus infection |
| Malignancies (Myeloma, Lymphoma) | Correlates with tumor burden | Very high ESR (>100 mm/hr) → poor prognosis |
For Non-Medicos: Understanding Your ESR Test
The Erythrocyte Sedimentation Rate (ESR), often called the “sed rate,” is a straightforward blood test that helps doctors identify inflammation inside your body. Think of it as a helpful warning light; when you have an illness or infection, your red blood cells tend to clump together into stacks and fall to the bottom of a test tube much faster than healthy blood would.
Why do doctors request this test?
Because the ESR test is not specific to one single disease, it acts as a broad “smoke detector”. It does not tell the doctor exactly what is wrong, but it signals that inflammation is present somewhere in your system. Doctors rely on this test to track how you are doing with conditions like infections, autoimmune issues, or even to monitor if a specific treatment for a long-term illness is actually working. If your levels start to drop during treatment, it is a very good sign that the therapy is effective.
Important things for patients to know:
The Process: Your blood is collected into a special tube with an anticoagulant to keep it from clotting. A lab professional then places this blood in a thin, upright tube and watches how far the red blood cells fall in one hour.
Timing Matters: For the most accurate results, the lab should ideally start the test within two hours of drawing your blood.
Normal Results: “Normal” can change based on your age and gender, which is why your doctor is the only one who can properly interpret what your specific result means in the context of your overall health.
Context is Key: Always remember that an abnormal result is not always a cause for panic, as many common factors like pregnancy or mild anaemia can influence the numbers. Always consult your healthcare provider to discuss what these results mean for you.
References:
Wintrobe, M. M. (1933). A macroscopic examination of the blood. American Journal of the Medical Sciences, 185(1), 58-71.
Westergren, A. (1921). Studies of the suspension stability of the blood. Acta Medica Scandinavica, 54(1), 247-282.
Brigden, M. L. (1999). Clinical utility of the erythrocyte sedimentation rate. American Family Physician, 60(5), 1443-1450.
Bedell, S. E., & Bush, B. T. (1985). Erythrocyte sedimentation rate: from folklore to facts. The American Journal of Medicine, 78(6), 1001-1009.
International Council for Standardization in Haematology (ICSH). (1993). Recommendations for measurement of erythrocyte sedimentation rate of human blood. American Journal of Clinical Pathology, 100(3), 339-343.
Jou, J. M., Lewis, S. M., Briggs, C., et al. (2011). ICSH review of the measurement of the erythrocyte sedimentation rate. International Journal of Laboratory Hematology, 33(2), 125-132.
Sox, H. C., & Liang, M. H. (1986). The erythrocyte sedimentation rate: guidelines for rational use. Annals of Internal Medicine, 104(4), 515-523.
Bottiger, L. E., & Svedberg, C. A. (1967). Normal erythrocyte sedimentation rate and age. British Medical Journal, 2(5544), 85-87.
Detwiler, D. A., & Tierno, P. M. (1990). The erythrocyte sedimentation rate. Laboratory Medicine, 21(9), 565-569.
Madan, N., & Sharma, U. (2012). Erythrocyte sedimentation rate: old and new perspectives. Journal of Hematology and Transfusion, 1(1), 1-5.
Bray, C., Bell, L. N., Liang, H., et al. (2016). Erythrocyte sedimentation rate and C-reactive protein measurements and their relevance in clinical practice. WMJ: Official Publication of the Wisconsin Medical Society, 115(6), 317-321.
Plebani, M. (2009). The erythrocyte sedimentation rate: still a useful test? Clinica Chimica Acta, 402(1-2), 213-214.
Al-Momen, A. K., & Al-Amri, A. (2000). The erythrocyte sedimentation rate: a revisit. Saudi Medical Journal, 21(1), 9-12.
O’Connell, J. B., & Kelleher, A. A. (2005). The ESR in clinical practice. The Journal of the Irish Medical Association, 98(3), 85-86.
FAQ’s:
What is the ESR test?
It measures how quickly red blood cells settle in an anticoagulated blood sample.Why is ESR performed?
It is a non-specific test used to detect inflammation throughout the human body.How is ESR measured?
It is measured by the Westergren method, Wintrobe method, or an automated analyzer.What tube is required?
A light blue-capped sodium citrate tube is required for collecting blood for this specific test.When to start testing?
The procedure should ideally begin within two hours of the initial blood collection.What is a Westergren tube?
A 300 mm long tube used for sedimentation rate measurement in clinical haematology.How is blood prepared?
Blood is mixed with sodium citrate and placed in a vertical rack for one hour.What do results indicate?
Results help monitor disease activity and therapeutic response for various inflammatory conditions.What causes high ESR?
Infections, pregnancy, anemia, cancer, and chronic autoimmune disorders can increase the sedimentation rate.What causes low ESR?
Polycythemia, sickle cell anemia, leukemia, and congestive heart failure can decrease the sedimentation rate.
