Blood Analysis Essay, Research Paper

Blood is a fluid substance that circulates in the arteries and veins of the

body. Blood is bright red or scarlet when it has been oxygenated in the lungs

and passes into the arteries; it becomes bluish red when it has given up its

oxygen to nourish the tissues of the body and is returning to the lungs through

the veins and the tiny vessels called capillaries. In the lungs, the blood gives

up the carbon dioxide wastes it has taken from the tissues, receives a new

supply of oxygen, and begins a new cycle. This movement of blood is brought

about by the coordinate activity of the heart, lungs, and blood vessels. Blood

is composed of a yellowish fluid, called plasma, in which are suspended the

millions of cells that constitute about 45 percent by volume of whole blood. It

has a characteristic odor and a specific gravity between 1.056 and 1.066. In an

average healthy adult, the volume of blood is one-eleventh of the body weight,

or between 4.5 and 6 liters (5 and 6 qt). A great portion of the plasma is

composed of water, a medium that facilitates the circulation of the many

indispensable factors of which blood is composed. A cubic millimeter of human

blood contains about 5 million red corpuscles called erythrocytes; 5000 to

10,000 white corpuscles called leukocytes; and 200,000 to 300,000 platelets

called thrombocytes. The blood also carries many salts and organic substances in

solution. Blood type, in medicine, classification of red blood cells by the

presence of specific substances on their surface. Typing of red blood cells is a

prerequisite for blood transfusion. In the early part of the 20th century,

physicians discovered that blood transfusions often failed because the blood

type of the recipient was not compatible with that of the donor. In 1901 the

Austrian pathologist Karl Landsteiner classified blood types and discovered that

they were transmitted by Mendelian heredity . The four blood types are known as

A, B, AB, and O. Blood type A contains red blood cells that have a substance A

on their surface. This type of blood also contains an antibody directed against

substance B, found on the red cells of persons with blood type B. Type B blood

contains the reverse combination. Serum of blood type AB contains neither

antibody, but red cells in this type of blood contain both A and B substances.

In type O blood, neither substance is present on the red cells, but the

individual is capable of forming antibodies directed against red cells

containing substance A or B. If blood type A is transfused into a person with B

type blood, anti-A antibodies in the recipient will destroy the transfused A red

cells. Because O type blood has neither substance on its red cells, it can be

given successfully to almost any person. Persons with blood type AB have no

antibodies and can receive any of the four types of blood; thus blood types O

and AB are called universal donors and universal recipients, respectively. Other

hereditary blood-group systems have subsequently been discovered. The hereditary

blood constituent called Rh factor is of great importance in obstetrics and

blood transfusions because it creates reactions that can threaten the life of

newborn infants. Blood types M and N have importance in legal cases involving

proof of paternity. A chemist uses liquid chromatography to analyze a complex

mixture of substances. The chromatograph utilizes an adsorbtive medium, which

when placed in contact with a sample, adsorbs the various constituents of the

sample at different rates. In this manner, the components of a mixture are

separated. Chromatography has many valuable applications, such as determining

the level of pollutants in air, analyzing drugs, and testing blood and urine

samples. Gas chromatography separates the volatile constituents of a sample, and

liquid/liquid chromatography separates small, neutral molecules in solution. The

goal in conducting a separation is to produce a purified or partly purified form

of the desired constituent for analytical measurement, or to eliminate other

constituents that would interfere with the measurement, or both. Separation is

often unnecessary when the method is highly specific, or selective, and responds

to the desired constituent while ignoring others. Measuring the pH, or hydrogen

ion content, of blood with a glass electrode is an example of a measurement that

does not require a separation step. QHP 7694 Head Space Sampler is a machine

that equilibrates the sample vials at the desired temperature for the specified

time period. A needle then punctures the teflon coated septum at the top of the

vial and draws a measured sample of the vapor which it sends to the Gas

Chromatograph. HP 5890 Gas Chromatograph. This machine takes the vapor from the

Head Space Sampler and passes it through a packed column designed specifically

for alcohol in blood. As the vapor passes through this column, different

compounds will travel at different rates thus exiting at different times. As the

separated compounds exit, they pass through a Flame Ionizing Device (FID) which

consists of a hydrogen-oxygen flame and ionizing detectors. The intensity of the

ionization is measured and sent to the computer for processing. Helium Carrier

Gas carries the vapors through the Gas Chromatograph. A Power Macintosh 7600 is

used for report generation, correspondence and on line communication. Reports

are printed using a variety of laser printers to insure optimum print quality.

Blood samples are quantitatively added to an aqueous solution into which an

internal standard has been added in order to compensate for sampling

fluctuations within the Gas Chromatograph. Static head space methodology is

employed in which an aliquot of equilibrated vapor is injected and analyzed by a

Flame Ionization Detector in the Gas Chromatograph,which consists of a

hydrogen-oxygen flame and ionizing detectors. The intensity of the ionization is

measured and sent to the computer for processing. Helium Carrier Gas carries the

vapors through the Gas Chromatograph. Blood analysis is very important in many

different situations. For example, in forensics, if a bloodstain pattern is

obtained, analysis is vital. BPA (Bloodstain Pattern Analysis) may on many

occasions, clearly define the location of the victim or the assailant by

establishing the actions of either or both. Possible and impossible scenarios

may be established to determine if the victim, witness, orassailant is

accurately describing what took place. Some questions that may be answered are:

What type of weapon or impact occurred to cause the bloodstains present? How

many times was the victim struck ? Where was the victim at the time the injuries

were inflicted? Where was the assailant during and following the assault? Is the

bloodstain evidence consistent with the medical examiner findings? Is the

bloodstain evidence on the suspect and his clothing consistent with the crime

scene? Numerous courts throughout the country have upheld the value and

scientific reliability of BPA. Court case information is available upon request.

BPA is a valuable asset during and after the initial investigation. BPA has been

extremely valuable during the establishment of the courtroom trial strategy.

Blood analysis can be very important in testing for drugs. If drugs are in your

system, your blood can be tested using more sophisticated means than static head

space gas chromatography. You can also use urine tests and breath tests. Urine,

however is the least reliable, while blood is the most. DNA Detection is a very

important part of blood analysis. Thanks to a powerful biochemical tool called

polymerase chain reaction (PCR), it is possible to detect incredibly tiny

amounts of particular DNA molecules. Even one single molecule can be enough! DNA

(deoxyribonucleic acid) is the central molecule of life. It contains sequences

of information coded along its length. The information tells cells how to build

protein molecules. PCR uses proteins called enzymes, combined with small pieces

of DNA called primers. The primers match the sequence of the target molecule

(the one being looked for) and the enzymes make lots more of any matching

molecules. The result is that one matching molecule is multiplied into billions!

DNA is very important because nobody has the same DNA pattern. Every single

person?s is different. DNA also lasts forever, it never disappears.

http://www.letsfindout.com/subjects/body/rfipulma.html http://www.watchtower.org/medical_care_and_blood.htm

http://www.letsfindout.com/subjects/body/veins.html http://www.encyclopedia.com/articles/01579.html

http://www.letsfindout.com/subjects/body/rfiblood.html "Blood" -

Encarta Encyclopedia "Blood Type" – Encarta Encyclopedia

"Forensics"- Encarta Encyclopedia