What Is ESR (Erythrocyte Sedimentation Rate)

What is ESR

ESR (Erythrocyte Sedimentation Rate) is one of the oldest and most widely used blood tests that measures non-specific inflammation in the body.

The principle is simple: blood is poured into a special tube and left to stand for one hour. Red blood cells (erythrocytes) gradually settle to the bottom. The faster they settle, the higher the ESR. During inflammation, certain proteins (fibrinogen, globulins) increase in the blood, causing erythrocytes to clump into rouleaux and settle faster.

It is important to understand: ESR is not a diagnostic test — it does not identify the source or type of inflammation. It is like a thermometer: it shows that something is happening, but does not explain what exactly.

Reference ranges

ESR is measured in mm/hr. Reference ranges differ by sex:

• Men: less than 15 mm/hr
• Women: less than 20 mm/hr

Important note: with age, the ESR reference limit naturally rises. Some sources suggest an approximate formula: for men — age divided by 2, for women — (age + 10) divided by 2. This means that for a 70-year-old, an ESR of 30–35 mm/hr may be less concerning than for a 30-year-old.

Why ESR may be elevated

An elevated ESR is a non-specific signal — it may be associated with many different conditions:

• Infections: bacterial infections usually raise ESR more than viral ones. During acute infections, ESR can reach 100 mm/hr and above.
• Autoimmune diseases: rheumatoid arthritis, systemic lupus erythematosus, and other autoimmune diseases are often associated with persistently elevated ESR.
• Oncological diseases: some forms of cancer (especially lymphomas, myeloma) can significantly raise ESR.
• Anaemia: a low red blood cell count changes their sedimentation dynamics and can artificially elevate ESR.
• Pregnancy: ESR increases during pregnancy, and this is physiologically normal.
• Obesity: excess weight is associated with slightly elevated ESR due to chronic low-grade inflammation.
• Older age: as mentioned, reference limits rise with age.

Why ESR may be low

A very low ESR is usually not clinically significant, but some conditions can lower it:

• Polycythaemia: an excess of red blood cells impedes their sedimentation.
• Sickle cell anaemia: abnormally shaped erythrocytes settle more slowly.
• Certain medications: corticosteroids and other immunosuppressants can lower ESR.
• Very low fibrinogen levels: in rare cases of coagulation system disorders.

What to do next

If ESR is elevated, it is recommended to evaluate it together with other inflammatory markers, primarily C-reactive protein (CRP). CRP responds faster (within hours), while ESR rises more slowly (over days), so both together provide a more complete picture.

From a lifestyle perspective, reducing chronic inflammation is supported by:

• A balanced diet rich in vegetables, fruits, and omega-3 fatty acids.
• Regular moderate-intensity physical activity.
• Adequate sleep and stress management.
• Weight normalisation if there is excess.

Monitoring over time

ESR is a good tool for monitoring chronic inflammation because it responds to slower changes than CRP. This is especially useful for monitoring autoimmune disease activity or treatment effectiveness.

If ESR was elevated due to an acute infection, it should normalise within 2–4 weeks after recovery. If ESR remains high for a long time without a clear cause, this is a signal for deeper investigation. Annual ESR monitoring alongside CRP is an informative part of an inflammatory profile.

Questions for your doctor

1. Does my ESR deviation require additional tests, and which ones specifically? 2. Were CRP or other inflammatory markers tested at the same time? 3. Should my age be taken into account when evaluating this result? 4. How long should I wait before repeating the test if I have just recovered from an infection? 5. Are there symptoms I should watch for and seek urgent attention?

*This is not medical advice. Consult your doctor regarding any health decisions.*