| | | | | | The Medical Algorithms Project |
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| Chapter : | ch3. Hematology | Section : | Erythrocyte Sedimentation Rate (ESR) | | Factors That Can Affect the Erythrocyte Sedimentation Rate (ESR) | | Copyright (c) 2006-2007, Institute for Algorithmic Medicine, Houston, TX, USA. All rights reserved. |
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Overview :
Elevations of the ESR are typically 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
factors. While clinically useful in primary care, the general 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.
| | References: | |
Jacobs DS,
DeMott WR, Oxley DK (editors). Jacobs & DeMott Laboratory Test Handbook, 5th
Edition. Lexi-Comp, Inc. 2001. pages 484-485.
Jurado RL.
Why shouldn't we determine the erythrocyte sedimentation rate? Clin Infect Dis.
2001; 33: 548-549.
Wallach J.
Interpretation of Diagnostic Tests, Seventh Edition. Lippincott Williams &
Wilkins. 2000. pages 56-57
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