erythrocyte sedimentation rate

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Erythrocyte Sedimentation Rate

 

Definition

The erythrocyte sedimentation rate (ESR), or sedimentation rate (sed rate), is a measure of the settling of red blood cells in a tube of blood during one hour. The rate is an indication of inflammation and increases in many diseases.

Purpose

ESR is increased in rheumatoid diseases, most infections, and in cancer. An advanced rate doesn't diagnose a specific disease, but it does indicate that an underlying disease may be present.
A physician can use ESR to monitor a person with an associated disease. When the disease worsens, the ESR increases; when the disease improves, the ESR decreases. The ESR doesn't always follow the course of cancer.
ESR is called an acute-phase reactant test, meaning that it reacts to acute conditions in the body, such as infection or trauma. The rate increase follows a rise in temperature and white blood cells count, peaks after several days, and usually lasts longer than the elevated temperature or white blood cells count.

Precautions

The ESR should not be used to screen healthy persons for disease.

Description

The ESR test is a simple test dating back to the ancient Greeks. A specific amount of diluted, unclotted blood is placed in a special narrow tube and left undisturbed for exactly one hour. The red cells settle towards the bottom of the tube, and the pale yellow liquid (plasma) rises to the top. After 60 minutes, measurements are taken of the distance the red cells traveled to settle at the bottom of the tube. Two methods, the Westergren and the Wintrobe, are used by laboratories; each method produces slightly different results. Most laboratories use the Westergren method.
Normally red cells don't settle far toward the bottom of the tube. Many diseases make extra or abnormal proteins that cause the red cells to move close together, stack up, and form a column (rouleaux). In a group, red cells are heavier and fall faster. The faster they fall, the further they settle, and the higher the ESR.
The ESR test is covered by insurance when medically necessary. Results are usually available the same or following day.

Preparation

This test requires 7mL-10 mL of blood. A healthcare worker ties a tourniquet on the patient's upper arm, locates a vein in the inner elbow region, and inserts a needle into that vein. Vacuum action draws the blood through the needle into an attached tube. Collection of the sample takes only a few minutes.

Aftercare

Discomfort or bruising may occur at the puncture site. Pressure applied to the puncture site until the bleeding stops reduces bruising. Warm packs to the puncture site relieve discomfort. The patient may feel dizzy or faint.

Normal results

A normal value does not rule out disease. Normal values for the Westergren method are: Men 0 mm/hour-15 mm/hour; women 0 mm/hour-20 mm/hour; and children 0 mm/hour-10 mm/hour.

Abnormal results

The highest ESR levels are usually seen in a cancer of a certain type of white blood cell (multiple myeloma) and rheumatoid disease, such as rheumatoid arthritis. Many other diseases also increase the ESR: infection, kidney disease, anemia, diseases involving white blood cells, cancer, and autoimmune and inflammatory diseases.
Any disease that changes the shape and size of red blood cells decreases the ESR. Distorted cells, such as with sickle cell disease, do not stack, and consequently do not settle far, even in the presence of an ESR-associated disease. Diseases that cause the body to make less protein or extra red blood cells also decrease the ESR.

Key terms

Acute phase reactant — A substance in the blood that increases as a response to an acute conditions such as infection, injury, tissue destruction, some cancers, burns, surgery, or trauma.
Erythrocyte sedimentation rate (ESR) — The distance that red blood cells settle in a tube of blood in one hour. It is an indication of inflammation.
Rouleaux — The stacking up of red blood cells, caused by extra or abnormal proteins in the blood that decrease the normal distance red cells maintain between each other.

Resources

Periodicals

Saadeh, Constantine. "The Erythrocyte Sedimentation Rate: Old and New Clinical Applications." Southern Medical Journal March 1998: 220-255.

erythrocyte

 [ĕ-rith´ro-sīt]
one of the formed elements in the peripheral blood, constituting the great majority of the cells in the blood. (For immature forms see erythrocytic series.) In humans the normal mature erythrocyte is a biconcave disk without a nucleus, about 7.7 micrometers in diameter, consisting mainly of hemoglobin and a supporting framework called the stroma. Erythrocyte formation (erythropoiesis) takes place in the red bone marrow in the adult, and in the liver, spleen, and bone marrow of the fetus. It requires an ample supply of dietary elements such as iron, cobalt, copper, amino acids, and certain vitamins. Called also red cell or corpuscle and red blood cell or corpuscle

The functions of erythrocytes include transportation of oxygen and carbon dioxide. They owe their oxygen-carrying ability to hemoglobin, a combination of an iron-containing prosthetic group (heme) with a protein (globin). Hemoglobin attracts and forms a loose connection with free oxygen, and its presence enables blood to absorb some 60 times the amount of oxygen that the plasma by itself absorbs. Oxyhemoglobin is red, which gives oxygenated blood its red color. Erythrocytes are stored in the spleen, which acts as a reservoir for the blood system and discharges the cells into the blood as required. The spleen may discharge extra erythrocytes into the blood during emergencies such as hemorrhage or shock.

Erythrocytes also are important in the maintenance of a normal acid-base balance, and, since they help determine the viscosity of the blood, they also influence its specific gravity. Their average life span is 120 days. They are subjected to much wear and tear in circulation and eventually are removed by cells of the reticuloendothelial system, particularly in the liver, bone marrow, and spleen. In spite of this constant destruction and production of erythrocytes, the body maintains a fairly constant number, between 4 and 5 million per mm3 of blood in women and 5 to 6 million per mm3 in men. A decreased number constitutes one form of anemia.

Erythrocytes are destroyed whenever they are exposed to solutions that are not isotonic to blood plasma. If they are placed in a solution that is more dilute than plasma (distilled water for example) the cells will swell until osmotic pressure bursts the cell membrane. If they are placed in a solution more concentrated than plasma, the cells will lose water and shrivel or crenate. It is for this reason that solutions to be given intravenously must be isotonic to plasma.

Aged red cells are ingested by macrophages in the spleen and liver. The iron is transported by the plasma protein transferrin to the bone marrow, where it is incorporated into new red cells. The heme group is converted to bilirubin, a bile pigment secreted by the liver. About 180 million red blood cells are destroyed every minute. Since the number of cells in the blood remains more or less constant, this means that about 180 million red blood cells are manufactured every minute.

Determination of the red blood cell volume is usually done as a preliminary step in determination of the total blood volume. A radioactive substance, usually chromium, is used to “tag” cells of a sample of blood drawn from the patient. The sample is then reintroduced into the circulating blood and subsequent samples are taken to be evaluated for degree of radioactivity. The degree of dilution is used to calculate total blood volume.
The events in the life of erythrocytes. Nucleated red blood cell (RBC) precursors stimulated by erythropoietin form erythrocytes in the bone marrow. Normal synthesis of hemoglobin occurs only in the presence of nutrients, iron, vitamin B12, and folic acid. Mature RBCs are released into circulation. The old or defective RBCs are degraded in the spleen. Iron and globin are reutilized immediately. Bilirubin is released in bile into the intestine. From Damjanov, 1996.
erythrocyte protoporphyrin test EP test; a screening test for lead toxicity; erythrocyte protoporphyrin levels are determined by direct fluorometry of whole blood or fluorescence analysis of whole blood extracts. Levels will be increased in either lead poisoning or iron deficiency.
erythrocyte sedimentation rate the rate at which erythrocytes settle out of unclotted blood in one hour. The test is based on the fact that inflammatory processes cause an alteration in blood proteins, resulting in aggregation of the red cells, which makes them heavier and more likely to fall rapidly when placed in a special vertical test tube. Normal ranges vary according to the type of tube used, each type being of a different size. The most common methods and the normal range for each are: Wintrobe method, 0 to 6.5 mm per hour for men, 0 to 15 mm per hour for women; and Westergren method, 0 to 15 mm per hour for men, 0 to 20 mm per hour for women.ƒ

The erythrocyte sedimentation rate is often inconclusive and is not considered specific for any particular disorder. It is most often used as a gauge for determining the progress of an inflammatory disease such as rheumatic fever, rheumatoid arthritis, or a respiratory infection. The information provided by this test must be used in conjunction with results from other tests and clinical evaluations.

rate

 [rāt]
the speed or frequency with which an event or circumstance occurs per unit of time, population, or other standard of comparison.
adjusted rate a fictitious summary rate statistically adjusted to remove the effect of a variable, such as age or sex, to permit unbiased comparison between groups having different compositions with respect to these variables. See also crude rate and specific rate.
attack rate in the analysis of acute outbreaks of disease, the proportion of persons who are exposed to the disease during the outbreak who do become ill.
basal metabolic rate an expression of the rate at which oxygen is utilized in a fasting subject at complete rest as a percentage of a value established as normal for such a subject. Abbreviated BMR.
birth rate the number of live births in a geographic area in a defined period, usually one year, relative to some specified population. For the crude birth rate, it is the average total population or the midyear population in the area during the period. Specific birth rates for subsets of the population may also be calculated, for example, an age-specific birth rate is limited to the population of females of a defined age range.
case fatality rate the number of deaths due to a specific disease as compared to the total number of cases of the disease.
crude rate one giving the total number of events occurring in an entire population over a period of time, without reference to any of the individuals or subgroups within the population. See also adjusted rate and specific rate.
death rate the number of deaths in a certain period of time divided by the total of a given population. The crude death rate is the ratio of the number of deaths in a geographic area in one year divided by the average population in the area during the year. The age-specific death rate is the ratio of the number of deaths occurring in a specified age group to the average population of that group. The cause-specific death rate is the ratio of the number of deaths due to a specified cause to the average total population. Called also mortality rate.
Historic example of death rates (per 100,000) for leading causes of death for men aged 25–44 years. From Centers for Disease Control and Prevention: Morbidity and Mortality Weekly Report 42:483, 1993.
DEF rate an expression of dental caries experienced in primary teeth, calculated by adding number of those requiring filling (D), decayed teeth requiring extraction (E), and those that have already been successfully filled (F); missing primary teeth are not included in the calculation.
DMF rate an expression of the condition of the permanent teeth based on the number of teeth decayed, missing (or indicated for removal), and filled or bearing restorations. It is calculated by adding the number of carious permanent teeth requiring filling (D), carious ones requiring extraction (Mr), ones previously extracted because of caries (Mp), and permanent teeth (F).
dose rate the amount of any therapeutic agent administered per unit of time.
erythrocyte sedimentation rate (ESR) see erythrocyte sedimentation rate.
fatality rate the death rate in a specific group of persons simultaneously affected by some event or circumstances, such as a natural disaster.
fertility rate a measure of fertility in a defined population over a specified period of time, usually one year; particularly the general fertility rate, but also including more specific rates such as those for females of a given parity or a particular age range or that describing the completed rate for females who have finished childbearing.
fetal death rate the ratio of the number of fetal deaths in one year to the total number of both live births and fetal deaths in that year.
five-year survival rate an expression of the number of survivors with no trace of a given disease five years after each has been diagnosed or treated for the disease.
flow rate flow (def. 2).
forced expiratory flow rate forced expiratory flow.
general fertility rate the most widely used measure of fertility; the number of live births in a geographic area in a year per 1000 women of childbearing age, which is usually defined as age 15 to 44 years.
glomerular filtration rate an expression of the quantity of glomerular filtrate formed each minute in the nephrons of both kidneys, calculated by measuring the clearance of specific substances, e.g., inulin or creatinine.
growth rate an expression of the increase in size of an organic object per unit of time.
heart rate the number of contractions of the cardiac ventricles per unit of time (usually per minute).
incidence rate the risk of developing a particular disease during a given period of time; the numerator of the rate is the number of new cases during the specified time period and the denominator is the population at risk during the period. Compare prevalence r.
infant mortality rate the ratio of the number of deaths in one year of children less than one year of age to the number of live births in that year.
intrinsic rate in cardiac pacing terminology, the heart rate unaided by an artificial pacemaker, expressed in beats per minute (bpm). See also cycle length.
maternal mortality rate a rate in which the numerator is the number of maternal deaths ascribed to puerperal causes in one year; the number of live births in that year is often used as the denominator, although to make a true rate the denominator should be the number of pregnancies (live births plus fetal deaths). Called also puerperal mortality rate.
maximal expiratory flow rate (MEFR) maximal expiratory flow.
maximal midexpiratory flow rate (MMFR) maximal midexpiratory flow.
mendelian rate an expression of the numerical relations of the occurrence of distinctly contrasted mendelian characteristics in succeeding generations of hybrid offspring.
metabolic rate an expression of the amount of oxygen consumed by the body cells.
morbidity rate an inexact term that can mean either the incidence rate or the prevalence rate.
mortality rate death rate.
neonatal mortality rate the ratio of the number of deaths in one year of children less than 28 days of age to the number of live births in that year.
paced rate in cardiac pacing terminology, the rate of pulses of an artificial pacemaker, expressed as pulses per minute (ppm). See also cycle length.
perinatal mortality rate the ratio of the number of the sum of fetal deaths after 28 or more weeks of gestation (stillbirths) and deaths of infants less than 7 days of age in one time period and population to the sum of the number of live births and fetal deaths after 28 or more weeks of gestation (stillbirths) in that same time period and population.
postneonatal mortality rate the ratio of the number of deaths in a given year of children between the 28th day of life and the first birthday relative to the difference between the number of the live births and neonatal deaths in that year; the denominator is sometimes simplified, less correctly, to the number of live births. The ratio is sometimes approximated as the difference between the infant mortality rate and the neonatal mortality rate.
prevalence rate the number of people in a population who have a disease at a given time; the numerator is the number of existing cases of disease at a specified time and the denominator is the total population. Time may be a point or a defined interval, and is traditionally the former if unspecified. Compare incidence r.
puerperal mortality rate maternal mortality r.
pulse rate the rate of the pulse, measured as number of pulsations in an artery per unit of time; normally between 60 and 80 per minute in an adult.
respiration rate the number of inhalations and exhalations per unit of time, usually measured by observation of chest movements and averaging 16 to 20 per minute in an adult.
sedimentation rate the rate at which a sediment is deposited in a given volume of solution, especially when subjected to the action of a centrifuge; see also erythrocyte sedimentation rate.
slew rate in cardiac pacing, the rate, expressed in units of mV/msec, at which an R wave reaches peak amplitude; it represents the maximum rate of change of amplifier output voltage.
specific rate a rate that applies to a specific demographic subgroup, e.g., individuals of a specific age, sex, or race, giving the total number of events in relation only to that subgroup. See also adjusted rate and crude rate.
stillbirth rate fetal death rate.

e·ryth·ro·cyte sed·i·men·ta·tion rate (ESR),

the rate of settling of red blood cells in anticoagulated blood; increased rates are often associated with anemia or inflammatory states. See: respiratory frequency.

erythrocyte sedimentation rate (ESR)

the rate at which red blood cells settle out in a vertical column of anticoagulated whole blood, expressed in millimeters per hour. Blood is collected in an anticoagulant and allowed to form a sediment in a calibrated glass column. At the end of 1 hour the laboratory technician measures the distance the erythrocytes have fallen in the tube. Elevated sedimentation rates are not specific for any disorder but most commonly indicate the presence of inflammation. Inflammation causes an alteration of the blood proteins, which makes the red blood cells aggregate, becoming heavier than normal. The speed with which they fall to the bottom of the tube corresponds to the degree of inflammation. Serial evaluations of erythrocyte sedimentation rate are useful in monitoring the course of inflammatory activity in rheumatic diseases and, when performed with a white blood cell count, can indicate infection. Certain noninflammatory conditions, such as pregnancy, are also characterized by high sedimentation rates. The Westergren ESR is determined with a 200-mm Westergren tube. Values are higher for women in both methods and vary according to the method used. Normal findings by the Westergren method are up to 20 mm/hr for females and up to 15 mm/hr for males. Other diseases which alter blood proteins can also be called abnormal ESRs. Also called (informal) sedimentation rate. See also inflammation.

erythrocyte sedimentation rate

'sed' rate, ESR A test that measures the rate at which RBCs in venous blood settle to the bottom of a test tube, a nonspecific indicator of inflammation; ESR ↑ in collagen vascular disease, neoplasia, pregnancy, hyperproteinemia; ↓ in polycythemia, microcytosis, sickle cell anemia; it is used to monitor Pts with rheumatic diseases, as therapy may require frequent adjustment of doses. See C-reactive protein.

e·ryth·ro·cyte sed·i·men·ta·tion rate

(ESR) (ĕ-rith'rŏ-sīt sed'i-mĕn-tā'shŭn rāt)
The rate of settling of red blood cells in anticoagulated blood; increased rates are often associated with anemia or inflammatory states.

rate

(rat) [L. rata, calculated]
The speed or frequency of occurrence of an event, usually expressed with respect to time or some other known standard.

acquisition rate

In radiology, the speed with which medical images are recorded, usually expressed in images per second.

attack rate

The rate of occurrence of new cases of a disease.

basal metabolic rate

Abbreviation: BMR
The metabolic rate as measured 12 hr after eating, after a restful sleep, with no exercise or activity preceding testing, with elimination of emotional excitement, and at a comfortable temperature. It is usually expressed in terms of kilocalories per square meter of body surface per hour. It increases, for example, in hyperthyroidism. Synonym: resting energy expenditure

baseline fetal heart rate

Abbreviation: FHR
The average range of beats per minute recorded within a 10-min time frame. The normal range is between 120 and 160 beats per minute.

birth rate

The number of live births per 1000 in the population in a given year.

case rate

Morbidity rate.

case fatality rate

The percentage of individuals afflicted with an illness who die as a result of it.

concordance rate

The frequency with which a gene will be inherited or expressed by identical or fraternal twins.

death rate

The number of deaths in a specified population, usually expressed per 100,000 population over a given period, usually 1 year. Synonym: death-to-case ratio; mortality rate

delivery rate

In assisted reproduction technology, the number of newborn deliveries achieved in every one hundred follicular aspirations, embryo transfers, or stimulated cycles.

dose rate

The quantity of medicine or radiation administered per unit of time.

erythrocyte sedimentation rate

Abbreviation: ESR
See: sedimentation rate

false-negative rate

The rate of occurrence of negative test results in those who have the attribute or disease for which they are being tested.

false-positive rate

The rate of occurrence of positive test results in those who do not have the attribute or disease for which they are being tested.

fertility rate

The number of births per year per 1000 women between ages 15 and 44 in a given population.

fetal mortality rate

The number of fetal deaths per 1000 live births, usually per year.

growth rate

The rate at which an individual, tissue, or organ grows over time.

heart rate

Abbreviation: HR
The number of heartbeats per unit of time, usually expressed or written as number per minute. A normal resting heart rate for an adult is 60–100 beats per minute.

infant mortality rate

The number of deaths per year of live-born infants less than 1 year of age divided by the number of live births in the same year. This value is usually expressed as deaths per 100,000 live births.
See: neonatal mortality rate; perinatal mortality rate

infusion rate

The speed of administration of a solution in mL/hr.

CAUTION!

It is calculated by the following formula: Rate = (Dose × 60 × Body weight)/Concentration, in which the dose is in mcg/kg/min; 60 is in min/hr; weight is in kg; and the concentration of the substance in solution is in mcg/mL.
Enlarge picture
CAUSES OF MATERNAL DEATH

maternal mortality rate

The number of maternal deaths in 1 year from puerperal causes (such as those associated with pregnancy, childbirth, and the puerperium) within 42 days after delivery divided by the number of live births in that same year. This value is usually expressed as deaths per 100,000 live births. See: illustration

maximum midexpiratory flow rate

Abbreviation: MMFR
The average airflow during the middle half of a forced vital capacity effort.

metabolic rate

The rate of utilization of energy. This is usually measured at a time when the subject is completely at rest and in a fasting state. Energy used is calculated from the amount of oxygen used during the test.
See: basal metabolic rate; basal metabolism

morbidity rate

The number of cases per year of certain diseases in relation to the size of the population in which they occur. Synonym: case rate

mortality rate

Death rate.

neonatal mortality rate

The number of deaths in 1 year of infants aged 0 to 28 days divided by the number of live births in that same year.
See: maternal mortality rate; perinatal mortality rate

peak expiratory flow rate

The maximum rate of exhalation during a forced expiration, measured in liters per second or liters per minute. It is used as a test of airway obstruction.

perinatal mortality rate

The number of stillbirths (in which the gestation period was 28 weeks or more) in the first 7 days of life divided by the number of live births plus stillbirths in the same year. This value is usually expressed as deaths per 100,000 live births plus stillbirths.
See: infant mortality rate; neonatal mortality rate

periodontal disease rate

See: periodontal (Ramfjord) index

pulse rate

The number of heartbeats per unit of time that can be detected by palpating any accessible artery.

respiration rate

The number of breaths per unit of time.

sedimentation rate

Abbreviation: ESR (erythrocyte sedimentation rate)
A nonspecific laboratory test used as a marker of inflammation. In this test the speed at which erythrocytes settle out of unclotted blood is measured. Blood to which an anticoagulant has been added is placed in a long, narrow tube, and the distance the red cells fall in 1 hr is the ESR. Normally it is less than 10 mm/hr in men and slightly higher in women.

The speed at which the cells settle depends on how many red blood cells clump together. Clumping is increased by the presence of acute-phase proteins released during inflammation.

specific absorption rate

The rate at which electromagnetic energy is absorbed by a kilogram of tissue, usually expressed as the heat absorbed by the tissue, or as the power absorbed per unit of mass.

ventilation rate

Abbreviation: VR
The number of breaths per minute.

erythrocyte sedimentation rate

See BLOOD SEDIMENTATION RATE.

erythrocyte sedimentation rate

; ESR rate at which erythrocytes in a sample of blood sink; if plasma globular protein concentration is elevated (e.g. in inflammation), erythrocytes clump (undergo rouleaux formation) and sink more rapidly; normal ESR is <20; raised ESR (i.e. >20) shows in infection, inflammation, ischaemia, malignancy, trauma, severe anaemia, old age and in females; ESR is reduced in polycythaemia vera

erythrocyte sedimentation rate (ēˈ·riˑ·thrō·sīt seˈ·di·men·tāˑ·shn rātˑ),

n a measure of erythrocytes settling in a tube of blood within 1 hour. Used to diagnose infectious and inflammatory diseases as well as tumors, arthritis, heart conditions, and other disorders.

e·ryth·ro·cyte sed·i·men·ta·tion rate

(ESR) (ĕ-rith'rŏ-sīt sed'i-mĕn-tā'shŭn rāt)
The rate of settling of red blood cells in anticoagulated blood; increased rates are often associated with anemia or inflammatory states.