Erythrocyte Sedimentation Rate Flashcards
ESR is the
Distance in millimeters that the RBCs fall in 1 hour
It is used to detect and monitor the cause of inflammatory conditions such as
Rheumatoid arthritis
The ESR is directly proportional to the ____ and inversely proportional to _____
directly proportional = red cell mass
inversely proportional = plasma viscosity
Stages:
- Initial rouleaux formation
- Rapid settling of RBCs
- Final sedimentation of RBCs
Most commonly used method
Modified Westergen
Most sensitive method
Westergen
Reference value for Westergen:
Male:
0-50 yo = 0-15 mm
>50 yo = 0-20 mm
Female:
0-50 yo = 0-20 mm
>50 yo - 0-30 mm
Requires a smaller amount of blood
Wintrobe method
Reference value for Wintrobe method:
Male: 0-9 mm
Female: 0-20 mm
Anticoagulant used in Wintrobe method
Double oxalate
Anticoagulant used in Westergren
3.8% sodium citrate
Anticoagulant used in Modified Westergren
EDTA (diluted with 3.8% sodium citrate or 0.85% NSS)
⬆️High fibrinogen and globulins
⬆️ ESR
promotes rouleaux formation
⬇️Low albumin
⬆️ ESR
less albumin means less repulsion between RBCs
⬆️Lipid levels
⬆️ ESR
increased plasma viscosity facilitates RBC stacking
⬇️Anemia (Low RBC count)
⬆️ ESR
fewer RBCs allow faster sedimentation
⬆️Polycythemia vera
⬇️ESR
more RBCs increase plasma viscosity, slowing sedimentation
Abnormal RBC shapes
⬇️ESR
irregular shapes hinder rouleaux formation
⬆️Leukocytosis
⬇️ESR
excess EBCs interfere with rouleaux formation
⬆️Infection/inflammation
⬆️ESR
due to increased fibrinogen and acute-phase proteins
Delayed testing (>4 hours at room temp)
⬇️ESR
RBCs change shape, reducing rouleaux formation
Clotting (poor anticoagulation use
Invalid ESR result
Fibrin traps RBCs, preventing sedimentation
Hemolysis (RBC destruction)
⬇️ESR
free hemoglobin increases plasma viscosity
Titled ESR tube
⬆️False-high ESR
gravity speeds sedimentation
