I have gathered some online info for you. Please keep in mind that
Google Answers is not a source of authoritative medical advice; the
material posted below is for informational use, and should not be
regarded as a substitute for the services of a qualified medical
While a sed rate of 0 is not an average one for the general
population, very low or zero ESR rates are not unusual in a person who
has polycythemia. Note that the ESR is not a test which, in and of
itself, necessarily indicates a specific diagnosis. A decreased ESR
may accompany numerous conditions, one of which is polycythemia.
"In clinical practice, the ESR is determined by visual inspection of
the fall of blood/plasma boundary. The test applied to the blood of
patients with polycythemia vera gives low or zero sedimentation rate."
Optica Applicata: Diffraction measurement of erythrocyte sedimentation rate
"The erythrocyte sedimentation rate (ESR) determination is a commonly
performed laboratory test with a time-honored role. However, the
usefulness of this test has decreased as new methods of evaluating
disease have been developed. The test remains helpful in the specific
diagnosis of a few conditions, including temporal arteritis,
polymyalgia rheumatica and, possibly, rheumatoid arthritis. It is
useful in monitoring these conditions and may predict relapse in
patients with Hodgkin's disease. Use of the ESR as a screening test to
identify patients who have serious disease is not supported by the
A decreased ESR is associated with a number of blood diseases in which
red blood cells have an irregular or smaller shape that causes slower
In patients with polycythemia, too many red blood cells decrease the
compactness of the rouleau network and artifactually lower the ESR."
American Academy of Family Physicians: Clinical Utility of the
Erythrocyte Sedimentation Rate
"The ESR may be decreased by conditions that interfere with the
formation of rouleaux or increase the RBC surface-area-to-volume
ratio. Rouleaux formation is hindered by spherocytosis, sickle cell
disease, microcytosis, marked variation in RBC size (anisocytosis),
and some drugs. Polycythemia decreases the compactness of rouleaux
American Proficiency Institute: THE ERYTHROCYTE SEDIMENTATION RATE AND
ITS CLINICAL UTILITY
"Westergren ESR (normal: <= [age + 10]/2 for women and age/2 for men)"
Merck Manual: Vascular Disorders
"ESR (erythrocyte sedimentation rate) is a nonspecific screening test
for various diseases. This 1-hour test measures the distance (in
millimeters) that red blood cells settle in unclotted blood toward the
bottom of a specially marked test tube.
Adults (Westergren method):
Men under 50 years old: less than 15 mm/hr.
Men over 50 years old: less than 20 mm/hr.
Women under 50 years old: less than 20 mm/hr.
Women over 50 years old: less than 30 mm/hr...
Lower-than-normal levels occur with:
Congestive heart failure
Hypofibrinogenemia (decreased fibrinogen levels)
Low plasma protein (due to liver or kidney disease)
Sickle cell anemia"
U.S. National Library of Medicine: ESR
"What does the test result mean?
NOTE: A standard reference range is not available for this test.
Because reference values are dependent on many factors, including
patient age, gender, sample population, and test method, numeric test
results have different meanings in different labs...
Although a low ESR is not usually important, it can be seen with
polycythemia (a condition where a patient makes too many red blood
cells), with extreme leukocytosis (patient has too many white blood
cells), and with some protein abnormalities. Some changes in red cell
shape (such as sickle cells in sickle cell anemia) also lower the
Lab Tests Online: ESR
My Google search strategy:
Google Web Search: esr "erythrocyte sedimentation rate"
Google Web Search: "low esr" OR "low sed rate" blood
Google Web Search: "decreased OR reduced OR low esr" blood
Google Web Search: polycythemia esr OR "sed rate"
I hope this is helpful. If anything is unclear or incomplete, or if a
link doesn't work for you, please request clarification; I'll be glad
to offer further assistance before you rate my answer.
Clarification of Answer by
16 Nov 2006 10:25 PST
The ESR is never less than zero, since it is a measurement (to the
nearest millimeter) of the height of the blood's plasma above the
layer of red cells (erythrocytes).
An ESR of zero, while unusual, is considered "normal." Normality is
typically expressed as a range, and in the case of ESR levels, that
range varies widely.
"The test is subject to a number of technical errors and therefore the
first step in the investigation of an unexpected result is to repeat
the test. The rate of fall of red cells in anti-coagulated plasma is
influenced by a number of factors. Briefly, sedimentation is
influenced greatly by the extent to which the red cells form rouleaux
or large clumps of cells. This rouleaux formation is related to the
plasma proteins which overcome the negative surface charge on red
cells. The haematocrit also influences the ESR. Anaemia accelerates
sedimentation and polycythaemia retards it. Table 1 lists the factor
which tend to influence the ESR.
The normal range for ESR is 0-10mm."
SydPath: Interpreting the ESR
In this study of 749 normal persons, the median ESR was 11mm:
"In our study of patients with positive temporal artery biopsy for
giant cell arteritis, it varied between 4 and 140 mm/hr (Westergren)
(median 87.5 mm). We also evaluated ESR in 749 normal persons, and
their ESR ranged from 1-59 mm/hr (median 11 mm). We found that ESR
levels increase with age and are also higher in women than in men. In
the literature highly variable numbers are given for the normal
values: most laboratories described it as <10 mm/hr in men and <20
mm/hr in women; Miller et al.61 put forward a formula to calculate the
normal ESR: in men age divided by 2 and in women age+10 divided by
two. Our study suggested that a useful cutoff criterion for normal ESR
is <30 mm/hr in men and <35 mm/hr in women, with a sensitivity and
specificity of 92%. With the ESR values in our study varying between 4
and 140 mm/hr in giant cell arteritis patients and 1 and 59 mm/hr in
normal persons, there is an overlap in lower levels of ESR between the
University of Iowa Department of Ophthalmology: Management of AION
I hope this helps.