Blood test - AbsoluteAstronomy.com

A blood test is a laboratory

Medical laboratory

A medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of disease.-Departments:...

analysis performed on a blood

Blood

Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

sample that is usually extracted from a vein

Vein

In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...

in the arm using a needle

Hypodermic needle

A hypodermic needle is a hollow needle commonly used with a syringe to inject substances into the body or extract fluids from it...

, or via fingerprick

Fingerprick

Fingersticks and heelpricks are small superficial wounds that provide venous blood for some blood tests. Various methods are used to open the wound, which produces no more than a few drops of blood...

.

Blood tests are used to determine physiological and biochemical states, such as disease

Disease

A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

, mineral

Mineral

A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

content, drug effectiveness, and organ function. They are also used in drug test

Drug test

A drug test is a technical analysis of a biological specimen – for example urine, hair, blood, sweat, or oral fluid / saliva – to determine the presence or absence of specified parent drugs or their metabolites...

s. Although the term blood test is used, most routine tests (except for most haematology) are done on plasma or serum

Blood plasma

Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...

, instead of blood cells.

Extraction

Venipuncture

In medicine, venepuncture, venopuncture or venipuncture is the process of obtaining intravenous access for the purpose of intravenous therapy or for blood sampling of venous blood. This procedure is performed by medical laboratory scientists, medical practitioners, some EMTs, paramedics,...

is useful as it is a relatively non-invasive way to obtain cell

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

s and extracellular fluid

Extracellular fluid

Extracellular fluid usually denotes all body fluid outside of cells. The remainder is called intracellular fluid.In some animals, including mammals, the extracellular fluid can be divided into two major subcompartments, interstitial fluid and blood plasma...

(plasma

Blood plasma

) from the body for analysis. Since blood flows throughout the body, acting as a medium for providing oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

and nutrients, and drawing waste products back to the excretory systems for disposal, the state of the bloodstream affects, or is affected by, many medical conditions. For these reasons, blood tests are the most commonly performed medical test

Medical test

A diagnostic test is any kind of medical test performed to aid in the diagnosis or detection of disease. For example:* to diagnose diseases, and preferably sub-classify it regarding, for example, severity and treatability...

s.

If only a few drops of blood are needed, a fingerstick is performed instead of drawing blood from a vein.

Phlebotomist

Phlebotomist

Phlebotomists are individuals trained to draw blood from a live person or animal.Phlebotomists collect blood primarily by performing venipuncture and, for collection of minute quantities of blood, fingersticks. Blood may be collected from infants by means of a heel stick...

s, laboratory technicians and nurses are those charged with patient blood extraction. However, in special circumstances, and emergency situations, paramedic

Paramedic

A paramedic is a healthcare professional that works in emergency medical situations. Paramedics provide advanced levels of care for medical emergencies and trauma. The majority of paramedics are based in the field in ambulances, emergency response vehicles, or in specialist mobile units such as...

s and physician

Physician

A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

s sometimes extract blood. Also, respiratory therapists are trained to extract arterial blood for arterial blood gas

Arterial blood gas

An arterial blood gas is a blood test that is performed using blood from an artery. It involves puncturing an artery with a thin needle and syringe and drawing a small volume of blood. The most common puncture site is the radial artery at the wrist, but sometimes the femoral artery in the groin or...

es.

Biochemical analysis

A basic metabolic panel

Basic metabolic panel

A basic metabolic panel is a set of seven or eight blood chemical tests. It is one of the most common lab tests ordered by health care providers. It provides key information that has a variety of applications in guiding the medical management of a patient...

measures sodium

Sodium

Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...

, potassium

Potassium

Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

, chloride

Chloride

The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...

, bicarbonate

Bicarbonate

In inorganic chemistry, bicarbonate is an intermediate form in the deprotonation of carbonic acid...

, blood urea nitrogen

Blood urea nitrogen

The blood urea nitrogen test is a measure of the amount of nitrogen in the blood in the form of urea, and a measurement of renal function. Urea is a by- product from metabolism of proteins by the liver and is removed from the blood by the kidneys.-Physiology:The liver produces urea in the urea...

(BUN), magnesium

Magnesium

Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

, creatinine

Creatinine

Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body...

, and glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

. It also sometimes includes calcium

Calcium

Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

.

Some blood tests, such as those that measure glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

, cholesterol

Cholesterol

Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

, or for determining the existence or lack of STD, require fasting (or no food consumption) eight to twelve hours prior to the drawing of the blood sample.

For the majority of blood tests, blood is usually obtained from the patient's vein. However, other specialized blood tests, such as the Arterial blood gas

Arterial blood gas

, require blood extracted from an artery

Artery

Arteries are blood vessels that carry blood away from the heart. This blood is normally oxygenated, exceptions made for the pulmonary and umbilical arteries....

. Blood gas analysis of arterial blood is primarily used to monitor carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

and oxygen

Oxygen

levels related to pulmonary function, but it is also used to measure blood pH

In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

and bicarbonate

Bicarbonate

In inorganic chemistry, bicarbonate is an intermediate form in the deprotonation of carbonic acid...

levels for certain metabolic conditions.

While the regular glucose test

Glucose test

A glucose test is a type of blood test used to determine the amount of glucose in the blood. It is mainly used in screening for any prediabetes or diabetes...

is taken at a certain point in time, the glucose tolerance test

Glucose tolerance test

A glucose tolerance test is a medical test in which glucose is given and blood samples taken afterward to determine how quickly it is cleared from the blood. The test is usually used to test for diabetes, insulin resistance, and sometimes reactive hypoglycemia and acromegaly, or rarer disorders of...

involves repeated testing to determine the rate at which glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

is processed by the body.

White blood cells (including T-cells) are often counted.

Normal ranges

!Test>

Low	High	Unit	>- \| Sodium Sodium Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride... (Na)	136	145	mmol/L	>- \| Potassium Potassium Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are... (K)	3.5	5.5	mmol/L	>- \| Urea Urea Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....	2.5	6.4	mmol/L	blood urea nitrogen Blood urea nitrogen The blood urea nitrogen test is a measure of the amount of nitrogen in the blood in the form of urea, and a measurement of renal function. Urea is a by- product from metabolism of proteins by the liver and is removed from the blood by the kidneys.-Physiology:The liver produces urea in the urea... >- \| Urea Urea Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....	15	40	mg/dL	>- \| Creatinine Creatinine Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body... - male	62	115	μmol/L	>- \| Creatinine Creatinine Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body... - female	53	97	μmol/L	>- \| Creatinine Creatinine Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body... - male	0.7	1.3	mg/dL	>- \| Creatinine Creatinine Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body... - female	0.6	1.1	mg/dL	>- \| Glucose Blood sugar The blood sugar concentration or blood glucose level is the amount of glucose present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM , or 64.8 and 104.4 mg/dL... (fasting)	3.9	5.8	mmol/L	See also glycosylated hemoglobin Glycosylated hemoglobin Glycated hemoglobin is a form of hemoglobin that is measured primarily to identify the average plasma glucose concentration over prolonged periods of time. It is formed in a non-enzymatic glycation pathway by hemoglobin's exposure to plasma glucose... >- \| Glucose Blood sugar The blood sugar concentration or blood glucose level is the amount of glucose present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM , or 64.8 and 104.4 mg/dL... (fasting)	70	120	mg/dL

Molecular profiles

Protein electrophoresis
Protein electrophoresis
Protein electrophoresis is a method for analysing the proteins in a fluid or an extract. The electrophoresis may be performed with a small volume of sample in a number of alternative ways with or without a supporting medium: SDS polyacrylamide gel electrophoresis Protein electrophoresis is a method...

(general technique—not a specific test)
Western blot
Western blot
The western blot is a widely used analytical technique used to detect specific proteins in the given sample of tissue homogenate or extract. It uses gel electrophoresis to separate native proteins by 3-D structure or denatured proteins by the length of the polypeptide...

(general technique—not a specific test)
Liver function tests
Liver function tests
Liver function tests , are groups of clinical biochemistry laboratory blood assays designed to give information about the state of a patient's liver. The parameters measured include PT/INR, aPTT, albumin, billirubin and others...
Polymerase chain reaction
Polymerase chain reaction
The polymerase chain reaction is a scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence....

(DNA). DNA testing is today possible with even very small quantities of blood: this is commonly used in forensic science, but is now also part of the diagnostic process of many disorders.
Northern blot
Northern blot
The northern blot is a technique used in molecular biology research to study gene expression by detection of RNA in a sample. With northern blotting it is possible to observe cellular control over structure and function by determining the particular gene expression levels during differentiation,...

(RNA)
Sexually transmitted disease
Sexually transmitted disease
Sexually transmitted disease , also known as a sexually transmitted infection or venereal disease , is an illness that has a significant probability of transmission between humans by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex...

s

Cellular evaluation

Full blood count (or "complete blood count")
Hematocrit
Hematocrit
The hematocrit or packed cell volume or erythrocyte volume fraction is the percentage of the concentration of red blood cells in blood. It is normally about 45% for men and 40% for women...

and MCV
Mean corpuscular volume
The mean corpuscular volume, or "mean cell volume" , is a measure of the average red blood cell size that is reported as part of a standard complete blood count....

("mean corpuscular volume")
Erythrocyte sedimentation rate
Erythrocyte sedimentation rate
The erythrocyte sedimentation rate , also called a sedimentation rate or Biernacki Reaction, is the rate at which red blood cells sediment in a period of 1 hour...

(ESR)
Cross-matching
Cross-matching
Cross-matching blood, in transfusion medicine, refers to the complex testing that is performed prior to a blood transfusion, to determine if the donor's blood is compatible with the blood of an intended recipient, or to identify matches for organ transplants. Cross-matching is usually performed...

. Determination of blood type
Blood type
A blood type is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells . These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system...

for blood transfusion
Blood transfusion
Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...

or transplants
Organ transplant
Organ transplantation is the moving of an organ from one body to another or from a donor site on the patient's own body, for the purpose of replacing the recipient's damaged or absent organ. The emerging field of regenerative medicine is allowing scientists and engineers to create organs to be...
Blood cultures are commonly taken if infection is suspected. Positive cultures and resulting sensitivity results are often useful in guiding medical treatment.

Saliva tests

In 2008, scientists announced that the more cost effective saliva tests could eventually replace some blood tests, as saliva contains 20% of the proteins found in blood.

Microemulsion

February 2011: Canadian researchers have developed a microchip for blood tests. It is called microemulsion, a droplet of blood captured inside a layer of another substance. It can control the exact size and spacing of the droplets. The new test could improve the efficiency, accuracy and speed of laboratory tests while also doing it cheaply. The microchip costs $25, whereas the robotic dispensers currently in use cost around $10,000.

SIMBAS

March 2011: A team of researchers from UC Berkeley

University of California, Berkeley

The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...

, DCU

Dublin City University

Dublin City University is a university situated between Glasnevin, Santry, Ballymun and Whitehall on the Northside of Dublin in Ireland...

and University of Valparaíso have developed lab-on-a-chip

Lab-on-a-chip

A lab-on-a-chip is a device that integrates one or several laboratory functions on a single chip of only millimeters to a few square centimeters in size. LOCs deal with the handling of extremely small fluid volumes down to less than pico liters. Lab-on-a-chip devices are a subset of MEMS devices...

that can diagnose diseases within 10 minutes without the use of external tubing and extra components. It is called Self-powered Integrated Microfluidic Blood Analysis System (SIMBAS). It uses tiny trenches to separate blood cells from plasma (99 percent of blood cells were captured during experiments). Researchers used plastic components, to reduce manufacturing costs.

Extraction

Biochemical analysis

Normal ranges

Molecular profiles

Cellular evaluation

Saliva tests

Microemulsion

SIMBAS

See also