What factors determine the erythrocyte sedimentation rate

The erythrocyte sedimentation rate (ESR) is mainly influenced by plasma protein composition, red blood cell characteristics, inflammatory infections, anemia, and technical factors. Abnormal increase of detection value is common in pathological conditions such as infectious diseases, rheumatic immune diseases, malignant tumors, etc. Physiological increase may be related to menstruation, pregnancy or the elderly.

1. Plasma proteins:

Fibrinogen and immunoglobulin are key plasma proteins that affect erythrocyte sedimentation rate. When inflammation or infection occurs in the body, the synthesis of fibrinogen by the liver increases, and its asymmetric molecular structure promotes the stacking of red blood cells to form a string like structure, accelerating sedimentation. When there is an increase in abnormal immunoglobulins such as rheumatoid factor, it can also promote the aggregation of red blood cells through the action of charges.

2. Red blood cell characteristics:

The number, morphology, and membrane structure of red blood cells directly affect sedimentation rate. Anemic patients experience a decrease in red blood cell count, leading to a decrease in suspension resistance and a significant increase in erythrocyte sedimentation rate. Genetic diseases such as sickle cell anemia may result in a decrease in sedimentation rate due to abnormal red blood cell morphology. Changes in surface charge of red blood cells can also affect their aggregation. 3. Inflammatory infection: During bacterial infection, endotoxins stimulate macrophages to release interleukin-6, which promotes the synthesis of acute phase response proteins in liver cells. The ESR of infectious diseases such as tuberculosis and pneumonia continued to rise. Patients with chronic inflammation such as rheumatoid arthritis can use erythrocyte sedimentation rate as a monitoring indicator for disease activity.

4. Physiological status:

During menstruation, women may experience a temporary increase in erythrocyte sedimentation rate due to the shedding of tissue factors from the endometrium. After three months of pregnancy, the expansion of plasma volume leads to blood dilution, and the erythrocyte sedimentation rate can reach 40-80mm/h. Due to physiological elevation of plasma fibrinogen in elderly people over 60 years old, the normal reference value should be appropriately relaxed.

5. Testing technique: Improper proportion of anticoagulant during blood collection can lead to false elevation. Standard testing should use 3.8% sodium citrate 1:4 anticoagulant. Tilting the test tube beyond 3 degrees can cause a deviation of up to 30% in the results. The laboratory temperature needs to be controlled at 18-25 ℃, as high temperatures can accelerate the sedimentation of red blood cells. The test should be completed within 2 hours after blood collection. Regular monitoring of changes in erythrocyte sedimentation rate (ESR) can help evaluate disease progression, but it needs to be combined with specific indicators such as C-reactive protein for comprehensive judgment. Avoid vigorous exercise and high-fat diet before testing, and women of childbearing age should avoid menstruation. For patients with persistent abnormalities, it is recommended to improve immune fixation electrophoresis, bone marrow puncture and other examinations. Rheumatoid immune disease patients can have follow-up treatment effects every 3-6 months. Pay attention to daily observation for accompanying symptoms such as joint swelling and pain, persistent fever, etc. Controlling weight and regular exercise can help improve chronic inflammation.