Factors That Can Affect the Erythrocyte Sedimentation Rate (ESR)

Description

Elevations of the erythrocyte sedimentation rate (ESR) may be associated with increases in acute phase reactants (including fibrinogen), tumor necrosis factor and immunoglobulins secondary to infectious, immune-mediated or tumor-related conditions.

However, the erythrocyte sedimentation rate may be affected by many other factors. The resulting lack of specificity can limit its usefulness.

Hematologic Factors	Increases ESR	Decreases ESR
red blood cell count	anemia	polycythemia
red blood cell shape	macrocytosis, cold agglutinins, erythroid aggregates	sickling, microcytosis, spherocytosis
bile salts		high concentration (affects RBC membranes)
white blood cell count		extremely high WBC

Protein Factors	Increases ESR	Decreases ESR
fibrinogen	hyperfibrinogenemia	hypofibrinogenemia, dysfibrinogenemia
other serum proteins	increased gamma globulins, alpha globulins, beta globulins, or monoclonal proteins	hypogammaglobulinemia
dextran	high molecular weight dextran	low molecular weight dextran
coagulation system	heparin	DIC (low fibrinogen)

Factor	Increases ESR	Decreases ESR
temperature	fever	hypothermia
nutritional status	extreme obesity	cachexia
serum cholesterol	high serum cholesterol
diet		recent feeding
organ failures	renal failure	congestive heart failure
drugs		valproic acid, steroids, anti-inflammatory agents
gender of the patient	females, especially during pregnancy (not early)
age of the patient	advanced age

Technical Factor	Increases ESR	Decreases ESR
tube handling	tilting tube	vibration
anticoagulant	heparin as anticoagulant	clotted specimen
testing		delay in testing
specimen handling		refrigerated specimen

where:

• EDTA and sodium citrate do not affect the ESR.

• Rouleaux formation is the mechanism for several factors increasing the ESR.

Interpretation:

• If there is some suspicion that the ESR result is spurious, then other markers such as C-reactive protein should be performed.

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Factors That Can Affect the Erythrocyte Sedimentation Rate (ESR)

Description

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