Blood - Function and Products
Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). Medical terms related to blood often begin in hemo- or hemato- (BE: haemo- and haemato-) from the Greek word "haima" for "blood". Anatomically, blood is considered a connective tissue from both its origin in the bones and its function.
The primary function of blood is to supply nutrients (oxygen, glucose) and constitutional elements to tissues and to remove waste products (such as carbon dioxide and lactic acid). Blood also enables cells (leukocytes, abnormal tumor cells) and different substances (amino acids, lipids, hormones) to be transported between tissues and organs. Problems with blood composition or circulation can lead to downstream tissue dysfunction. Blood is also involved in homeostasis by acting as a medium for transferring heat to the skin and by acting as a buffer system for bodily pH.
The blood is circulated around the lungs and body by the pumping action of the heart. Additional return pressure may be generated by gravity and the actions of skeletal muscles.
Anatomy of Blood
Blood is composed of several kinds of corpuscles; these formed elements of the blood constitute about 40% of whole blood. The other 60% is blood plasma, a fluid that is the blood's liquid medium, appearing yellow in color. The normal pH of human arterial blood is approximately 7.40 (normal range is 7.35-7.45). Blood that has a pH below 7.35 is acidic, while blood pH above 7.45 is alkaline. Blood pH along with arterial carbon dioxide tension (PaCO2) and HCO3 readings are helpful in determining the acid-base balance of the body. Blood is about 7% of the human body weight , so the average adult has a blood volume of about 5 liters, of which 2.7-3 liters is plasma. The combined surface area of all the erythrocytes in the human anatomy would be roughly 2,000 times as great as the body's exterior surface.
The corpuscles are:
Red blood cells or erythrocytes (96%). In mammals, mature red blood cells lack a nucleus and organelles. They contain the blood's hemoglobin and distribute oxygen. The red blood cells (together with endothelial vessel cells and some other cells) are also marked by proteins that define different blood types.
White blood cells or leukocytes (3.0%), are part of the immune system; they destroy infectious agents.
Platelets or thrombocytes (1.0%) are responsible for blood clotting (coagulation)
Blood plasma is essentially an aqueous solution containing 96% water, 4% blood plasma proteins, and trace amounts of other materials. Some components are:
Blood clotting factors
Various other proteins
Various electrolytes (mainly sodium and chlorine)
Together, plasma and corpuscles form a non-newtonian fluid whose flow properties are uniquely adapted to the architecture of the blood vessels.
Physiology Of Blood
Production And Degradation
Blood cells are produced in the bone marrow; the process is termed hematopoiesis. The proteinaceous component is produced overwhelmingly in the liver, while hormones are produced by the endocrine glands and the watery fraction regulated by the hypothalamus and maintained by the kidney and indirectly by the gut.
Blood cells are degraded by the spleen and the Kupffer cells in the liver. The liver also clears proteins and amino acids. The kidney secretes many small proteins into the urine. Erythrocytes usually live up to 120 days before they are systematically replaced by new erythrocytes created by the process of hematopoiesis.
Transport of oxygen
Blood oxygenation is measured in several ways, but the most important measure is the hemoglobin saturation percentage. This is a non-linear (sigmoidal) function of the partial pressure of oxygen. About 98.5% of the oxygen in a sample of arterial blood in a healthy human breathing air at normal pressure is chemically combined with the Hb. Only 1.5% is physically dissolved in the other blood liquids and not connected to Hb. The hemoglobin molecule is the primary transporter of oxygen in mammals and many other species (for exceptions, see below).
With the exception of pulmonary and umbilical arteries and their corresponding veins, arteries carry oxygenated blood away from the heart and deliver it to the body via arterioles and capillaries, where the oxygen is consumed; afterwards, venules and veins carry deoxygenated blood back to the heart.
Differences in infrared absorption between oxygenated and deoxygenated blood form the basis for realtime oxygen saturation measurement in hospitals and ambulances.
Under normal conditions in humans, hemoglobin in blood leaving the lungs is about 96-97% saturated with oxygen; 'deoxygenated' blood returning to the lungs is still approximately 75% saturated. A fetus, receiving oxygen via the placenta, is exposed to much lower oxygen pressures (about 20% of the level found in an adult's lungs) and so fetuses produce another form of hemoglobin with a much higher affinity for oxygen (hemoglobin F) in order to extract as much oxygen as possible from this sparse supply.
Transport of carbon dioxide
When systemic arterial blood flows through capillaries, carbon dioxide diffuses from the tissues into the blood. Some carbon dioxide is dissolved in the blood. Some carbon dioxide reacts with hemoglobin to form carbamino hemoglobin. The remaining carbon dioxide is converted to bicarbonate and hydrogen ions. Most carbon dioxide is transported through the blood in the form of bicarbonate ions.
Transport of hydrogen ions
Some oxyhemoglobin loses oxygen and becomes deoxyhemoglobin. Deoxyhemoglobin has a much greater affinity for H+ than does oxyhemoglobin so it binds most of the hydrogen ions.
Color of Blood
In humans and other hemoglobin-using creatures, oxygenated blood is a bright red in its color. This is due to oxygenated iron in the red blood cells. Deoxygenated blood is a darker shade of red, which can be seen during blood donation and when venous blood samples are taken. However, due to an optical effect caused by the way in which light penetrates through the skin, veins typically appear blue in color. This has led to a common misconception that before venous blood is exposed to air it is blue.
Health and disease
Hippocratic medicine considered blood one of the four humors (together with phlegm, yellow bile and black bile). As many diseases were thought to be due to an excess of blood, bloodletting and leeching were a common intervention until the 19th century (it is still used for some rare blood disorders).
In classical Greek medicine, blood was associated with air, springtime, and with a merry and gluttonous (sanguine) personality. It was also believed to be produced exclusively by the liver.
Blood pressure and blood tests are amongst the most commonly performed diagnostic investigations that directly concern the blood.
Problems with blood circulation and composition play a role in many diseases.
Wounds can cause major blood loss (see bleeding). The thrombocytes cause the blood to coagulate, blocking relatively minor wounds, but larger ones must be repaired at speed to prevent exsanguination. Damage to the internal organs can cause severe internal bleeding, or hemorrhage.
Circulation blockage can also create many medical conditions from ischemia in the short term to tissue necrosis and gangrene in the long term.
Hemophilia is a genetic illness that causes dysfunction in one of the blood's clotting mechanisms. This can allow otherwise inconsequential wounds to be life-threatening, but more commonly results in hemarthrosis, or bleeding into joint spaces, which can be crippling.
Leukemia is a group of cancers of the blood-forming tissues.
Major blood loss, whether traumatic or not (e.g. during surgery), as well as certain blood diseases like anemia and thalassemia, can require blood transfusion. Several countries have blood banks to fill the demand for transfusable blood. A person receiving a blood transfusion must have a blood type compatible with that of the donor.
Blood is an important vector of infection. HIV, the virus which causes AIDS, is transmitted through contact between blood, semen, or the bodily secretions of an infected person. Hepatitis B and C are transmitted primarily through blood contact. Owing to blood-borne infections, bloodstained objects are treated as a biohazard.
Infection of the blood is bacteremia or sepsis. Malaria and trypanosomiasis are blood-borne parasitic infections.
Blood transfusion is the most direct therapeutic use of blood. It is obtained from human donors by blood donation. As there are different blood types, and transfusion of the incorrect blood may cause severe complications, crossmatching is done to ascertain the correct type is transfused.
Other blood products administered intravenously are platelets, blood plasma, cryoprecipitate and specific coagulation factor concentrates.
Many forms of medication (from antibiotics to chemotherapy) are administered intravenously, as they are not readily or adequately absorbed by the digestive tract.
As stated above, some diseases are still treated by removing blood from the circulation.
It is the fluid part of the blood that saves lives where severe blood loss occurs, other preparations can be given such as ringers atopical plasma volume expander as a non-blood alternative, and these alternatives where used are rivalling blood use where used.
Jehovah's Witnesses are prohibited from eating blood and accepting transfusions of whole blood or any of red cells, white cells, platelets, whole plasma. They are permitted to accept fractions, and the acute normovolemic hemodilution (ANH) and autologous blood salvage (cell saver) procedures.
A blood type is a description of an individual's characteristics of red blood cells due to substances (carbohydrates and proteins) on the cell membrane. The two most important classifications to describe blood types in humans are ABO and the Rhesus factor (Rh factor). There are 46 other known antigens, most of which are much rarer than ABO and Rh. Blood transfusions from incompatible groups can cause an immunological transfusion reaction, resulting in hemolytic anemia, renal failure, shock, and death.
The phrases "blood group" and "blood type" are often used interchangeably, although this is not technically correct. "Blood group" is used to refer specifically to a person's ABO status, while "blood type" refers to both ABO and Rh factors.
Blood type is determined by the antigens (epitopes) on the surface of a red blood cell. Some of these are proteins, while others are proteins with polysaccharides attached. The absence of some of these markers leads to production of antibodies against this marker. The exact reason why this happens is poorly understood, as generally an antigen needs to be present to elicit an immune response. Administration of the wrong blood type would lead to immediate destruction of the infused blood. The breakdown products cause acute medical illness; hence, it is of vital importance that the correct blood type of the donor and receptor is determined, and their blood properly matched.
Austrian scientist Karl Landsteiner is widely credited with the discovery of the main blood type system (ABO); he was awarded the Nobel Prize in Physiology or Medicine in 1930 for his work.
Humans have the following blood types along with their respective antigens and antibodies:
Individuals with type A blood have red blood cells with antigen A on their surface and produce antibodies against antigen B in their blood serum. Therefore an A-negative person can only receive blood from another A-negative person or from an O-negative person.
Individuals with type B blood have the opposite arrangement, antigen B on their cells and produce antibodies against antigen A in their serum. Therefore, a B-negative person can only receive blood from another B-negative person or from an O-negative person.
Individuals with type AB blood have red blood cells with both antigens A and B and do not produce antibodies against either antigen in their serum. Therefore, a person with type AB-positive blood can safely receive any ABO type blood and is called a "universal receiver". However an AB-positive person cannot donate blood except to another AB-positive person.
Individuals with type O blood have red blood cells with neither antigen but produce antibodies against both types of antigens. Therefore, a person with type O-negative blood can safely donate to a person with any ABO blood type and is called a "universal donor". However an O-negative person can only receive blood from another O-negative person.
Overall, the O blood type is the most common blood type in the world, although in some areas, such as Sweden and Norway, the A group dominates. The A antigen is overall more common than the B antigen. Since the AB blood type requires the presence of both A and B antigens, the AB blood type is the rarest of the ABO blood types. There are known racial and geographic distributions of the ABO blood types.
The precise reason why people develop antibodies against an antigen they have never been exposed to is unknown. It is believed that some bacterial antigens are similar enough to the A and B glycoproteins, and that antibodies created against the bacteria will react to ABO-incompatible blood cells.
Apart from red blood cells, the ABO antigen is also expressed on the glycoprotein von Willebrand factor (vWF), which participates in hemostasis (control of bleeding). In fact, blood type O predisposes very slightly to bleeding, as vWF is degraded more rapidly. ABO antigens are also present in many other tissues such as liver, kidneys and lungs.
The H antigen
The A & B antigens are derived from a common precursor known as the H antigen. The H antigen is a glycosphingolipid (sphingolipid with carbohydrates bonded to the ceramide moiety) which is modified to produce the A and B antigens. In type O blood, it remains unchanged and consists of a chain of glucose, galactose, N-acetyl galactosamine, and fucose attached to the ceramide.
Rhesus system (CDE)
Another characteristic of blood is Rhesus factor or Rh factor. It is named after the Rhesus monkey, in which the factor was first identified by Landsteiner. Someone either has or does not have the Rh factor on the surface of their red blood cells. This is indicated as + or -, and the two groups are described as Rh positive (Rh+) or Rh negative (Rh-), respectively. This is often combined with the ABO type. Type O+ blood is most common.
Matching the Rhesus factor is very important, as mismatching (an Rh positive donor to an Rh negative recipient) may cause the production in the recipient of an antibody to the Rh(D) antigen, which could lead to subsequent hemolysis. This is of particular importance in females of or below childbearing age, where any subsequent pregnancy may be affected by the antibody produced. For one-off transfusions, particularly in older males, the use of Rh(D) positive blood in an Rh(D) negative individual (who has no atypical red cell antibodies) may be indicated if it is necessary to conserve Rh(D) negative stocks for more appropriate use. The converse is not true: Rh+ patients do not react to Rh- blood.
Rh disease occurs when an Rh negative mother who has already had an Rh positive child (or an accidental Rh+ blood transfusion) carries another Rh positive child. After the first pregnancy, the mother develops IgG antibodies against Rh+ red blood cells, which can cross the placenta and hemolyze the red cells of the second child. This reaction doesn't always occur and is less likely to occur if the child carries either the A or B antigen and the mother does not. In the past, Rh incompatibility could result in stillbirth or death of the mother. At present, it can be treated with certain anti-Rh(+) antisera, the most common of which is Rhogam (anti-D).
ABO blood type incompatibilities between the mother and child do not cause a similar problem because antibodies to the ABO blood groups are of the IgM type, which do not cross the placenta.
Frequency of ABO and Rhesus
Blood types are not evenly distributed throughout the human population. O+ is the most common, AB- is the rarest. There are also variations in blood-type distribution within human subpopulations. The figures given here are for people of European descent.
Other blood types
There are 27 other blood type systems that exist to describe the presence or absence of other antigens. They exist alongside the ABO antigens, and hence one can be A Rh positive but in addition have Kell or Lewis positivity or negativity.
Diego positive blood is found only among East Asians and Native Americans.
MNS system gives blood types of M, N, and MN. It has use in tests of maternity or paternity.
Duffy negative blood gives partial immunity to malaria, and is found within African populations.
The Lutheran system describes a set of 21 antigens.
Duffy-type blood presents special problems for blood donation groups and recipients because it occurs in a relatively small segment of the African population, but can cause problems if the recipient isn't properly matched with Duffy-type blood.
These blood types systems are generally not significant for blood donations, but have applications in forensic science.
The rare individuals with Bombay phenotype (hh) do not express substance H on their red blood cells and therefore do not bind A or B antigens. Instead, they produce antibodies to H substance (which is present on all red cells except those of hh genotype) as well as to both A and B antigens and are therefore compatible only with other hh donors.
Individuals with Bombay phenotype blood groups can only be transfused with blood from other Bombay phenotype individuals. Given that this condition is very rare to begin with, any person with this blood group who needs an urgent blood transfusion may be simply out of luck, as it would be quite unlikely that any blood bank would have any in stock. Those anticipating the need for blood transfusion (e.g. in scheduled surgery) may bank blood for their own use (i.e. an autologous blood donation) but this option is not available in cases of accidental injury. The blood phenotype was first discovered in Bombay, now known as Mumbai, in India.
Blood tests are laboratory tests done on blood to gain an appreciation of disease states and the function of organs. Since blood flows throughout the body, acting as a medium for providing oxygen and other 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 tests. Blood is obtained from a patient by venipuncture, except for tests such as Arterial blood gas. This is not a reliable source.
Blood is useful as it is a relatively non-invasive way to obtain cells, and extracellular fluid (plasma), from the body to check on its health. Although the term blood test is used, most routine tests (except for most hematology) are done on plasma or serum.
The list below includes both specific tests, and general techniques.
Blood chemistry tests
The CHEM-7 test, sometimes referred to as the Basic Metabolic Profile or Panel (BMP), is a battery of blood chemistry tests. The seven parts of a CHEM-7 include tests for:
One common use for these tests is to determine renal function.
While the regular glucose test is taken at a certain point in time, the glucose tolerance test involves repeated testing to determine the rate at which glucose is processed by the body.
While the above tests are all taken from veinous blood, by contrast the arterial blood gas test is, as its name would suggest, taken from arterial blood, and is therefore more dangerous and uncomfortable.
Large organic molecules
Protein electrophoresis (general technique -- not a specific test).
Western blot (general technique -- not a specific test).
Liver function tests.
Serology (general technique -- not a specific test).
Wassermann test (for syphilis).
ELISA test .
Full blood count (or "complete blood count").
Hematocrit and MCV ("mean corpuscular volume").
Erythrocyte sedimentation rate (ESR).
Cross-matching. Determination of blood type for blood transfusion or transplants.
Blood cultures are commonly taken if infection is suspected. Positive cultures and resulting sensitivity results are often useful in guiding medical treatment.
Reference ranges for common blood tests
A reference range is a set of values used by a health professional to interpret a set of medical test results. The range is usually defined as the set of values 95% of the normal population falls within.
It must be remembered that the reference range will vary, depending on the age, sex and race of a population, and even the machines the laboratory uses to do the tests. Also remember that by definition 5% of the normal population will fall outside the reference range.
These are approximate adult values that are intended as a guide to students and those interested, they are not a substitute for medical advice.
Electrolytes and Metabolites
Test Range Comments
Sodium (Na) 130 - 145 mmol/L (UK 135-146 mmol/L)
Potassium (K) 3.5 - 5.0 mmol/L (UK - same)
Urea 2.6 - 6.8 mmol/L or 10 - 20 mg/dL (UK 2.5 - 6.7 mmol/L) (BUN -blood urea nitrogen)
Creatinine 50 - 110 μmol/L or <1.5 mg/dL (UK 79 - 118μmol/L)
Glucose (fasting) 4.2 - 6.1 mmol/L or 75-115 mg/dL (UK Fasting 4.5 - 5.6 mmol/L) glycosylated hemoglobin
Liver function tests
Total Protein 60 - 80 g/L
Albumin 30 - 50 g/L
Total Bilirubin 2 - 14 μmol/L
Direct Bilirubin 0 - 4 μmol/L
Alanine transaminase (ALT) 8 - 40 U/L Also called serum glutamic pyruvic transaminase (SGPT)
Alkaline phosphatase (ALP) 40 - 130 U/L Higher in children and pregnant women.
Gamma glutamyl transferase < 50 U/L
Other enzymes and proteins
Creatine kinase (CK) 22 - 198 U/L
Aspartate transaminase (AST) 8 - 35 U/L
Lactate dehydrogenase (LDH) 85 - 285 U/L
Amylase 25 - 125 U/L
C-reactive protein (CRP) <8 mg/L
D-dimer <500 ng/mL
Other ions and trace metals
Ionized calcium (Ca) 1.15 - 1.29 mmol/L Some calcium is bound to albumin, thus not measured by certain techniques.
Total calcium (Ca) 2.05 - 2.55 mmol/L
Copper (Cu) 11 – 26 μmol/L
Zinc (Zn) 10 – 17 μmol/L
Triglycerides 0.4 - 2.0 mmol/L
Total cholesterol 3.0 - 5.5 mmol/L
HDL cholesterol (male) 0.7 - 1.9 mmol/L
(female) 0.9 - 2.4 mmol/L
LDL cholesterol 2.4 - 4.0 mmol/L Not valid when triglycerides >5.0 mmol/L.
Alpha-fetoprotein (AFP) 1-15 kIU/L
CA-125 <65 kU/L
Prostate specific antigen (total PSA) <2.0 μg/L After age 40, normal levels increase every decade.
Thyroid stimulating hormone (TSH) 0.5 - 4.7 mIU/L Also called: Thyrotropin
Free thyroxine (FT4) 9.0 - 24 pmol/L
Free triiodothyronine (FT3) 2.5 - 5.3 pmol/L
Adrenocorticotropic hormone (ACTH) 1.3 - 15 pmol/L
Cortisol (0830 h) 250 - 850 nmol/L Cortisol levels are higher in the morning than at night.
Cortisol (1630 h) 110 - 390 nmol/L
Prolactin (male) <450 mIU/L
(female) <580 mIU/L
Testosterone (male) 8 - 38 nmol/L
(male prepuberty) 0.1 - 0.5 nmol/L
(female) 0.3 - 2.5 nmol/L
Red blood cells
Hemoglobin (Hb) (male) 130 - 180 g/L Higher in neonates, lower in children.
(female) 115 - 160 g/L Sex difference negligible until adulthood.
Hematocrit (Hct) (male) 0.38 - 0.52
(female) 0.35 - 0.47
Mean cell volume (MCV) 80 - 98 fL Cells are larger in neonates, though smaller in other children.
Mean cell hemoglobin (MCH) 26 - 34 pg
Red cell count (male) 4.5 - 6.5 x1012/L
(female) 3.8 - 5.8 x1012/L
Reticulocytes 10 - 100 x109/L
Erythrocytesedimentation rate (ESR) <20 mm/hr Females tend to have a higher ESR. ESR increases with age.
White blood cells
The Total white blood cells 4.0 - 11.0 x109/L Higher in neonates and infants.
Neutrophil granulocytes 2.0 - 7.5 x109/L 45-74% Also known as granulocytes (grans), polys, PMNs, or segs.
Lymphocytes 1.0 - 4.0 x109/L 16-45%
Monocytes 0.0 - 0.8 x109/L 4.0-10%
Eosinophil granulocytes 0.0 - 0.5 x109/L 0.0-7.0%
Basophil granulocytes 0.0 - 0.2 x109/L 0.0-2.0%
Platelets 150 - 400 x109/L Platelets are part of the formation of blood clots
Prothrombin time (PT) 7 - 10 s PT reference varies between laboratory kits - INR is standardized
INR 0.9 - 1.2 The INR is a corrected ratio of a patients PT to normal
Activated partial thromboplastin time (APTT) 29 - 41 s
Thrombin clotting time (TCT) 11 - 18 s
Fibrinogen 1.8 - 4.0 g/L
Bleeding time 2 - 9 minutes
Acute phase protein markers of Inflammation
Erythrocyte sedimentation rate (ESR) 0 - (Age, +10 if female)/2 mm/hr
C-reactive protein (CRP) 0-6 mg/L
Antinuclear antibodies (ANA)
Extractable nuclear antigen (ENA)
Rheumatoid factor (RF) 0 - 20 IU/mL High levels not specific for Rheumatoid Arthritis alone.
Antistreptolysin O titre (ASOT) <100 unit/mL for preschoolers and <200 units/mL for others
Blood Transfusion and Substitutes
Blood transfusion is the taking of blood or blood-based products from one individual and transferring them into the circulatory system of another. It can be considered as a form of organ transplant. Blood transfusions may treat medical conditions, such as massive blood loss due to trauma, surgery, shock and where the red cell producing mechanism fails.
Great care is taken to ensure that the recipient's immune system will not attack the donor blood, and also to avoid transfusing white blood cells that could initiate an immune attack on the host (graft versus host disease). Nevertheless, blood transfusion does suppress the immune system, increasing the risk of complications after surgery.
Possible complications in a recipient include:
Blood Substitutes and Products:
Sometimes only parts of the blood are taken for donation. Blood is made up mostly of plasma, red blood cells, white blood cells and platelets. Plasma and platelets can be donated separately in a process called apheresis. Blood is usually separated into components after being donated to make the most use of it. Donation of whole blood is generally reserved for treating young children and remote areas where the hospital summons donors when it needs them. Resulting blood component products also include albumin protein used to treat burns, clotting factor concentrates used to treat hemophilia, cryoprecipitate, fibrinogen concentrate, and immunoglobulin antibodies for immunological disorders.
Rather than using whole blood transfusions, doctors are now increasingly using individual blood components to treat the patients. Some of these blood products are mentioned below.
Whole Blood-Whole Blood contains one unit of plasma and cells. Whole blood can be stored normally for five weeks.
Red Blood Cells (RBCs)-One unit of red Blood cells (RBC) contains approximately 180 ml of red cells and approximately 30 ml of plasma. Red blood cells are indicated for patients with symptomatic anemia that is not treatable with specific therapy such as iron, vitamin B12 or with folic acid.
Washed Red Blood Cells-Washed red blood cells are red blood cells washed with normal saline to remove most of the plasma. Washed red cells can used in patients who have had repeated hypersensitivity reactions to blood or components despite prophylactic administration of antihistamines.
Leukoreduced Red Blood Cells-Leukoreduced red blood cell units contain leukocytes in a specifically reduced amount. Leukoreduced red cells are usually effective in preventing non-hemolytic febrile transfusion reactions for most patients and prevention of CMV transmission.
Pediatric/Divided RBC Units-Divided red blood cell units are indicated for infants who require small amounts of red cells.
Platelets-Platelets are cells essential for the coagulation of blood. Platelet products contain plasma, red cells and white cells (leukocytes). Platelet transfusions are indicated for patients with bleeding from thrombocytopenia or platelet dysfunction.
Granulocytes (Neutrophils)-Granulocytes are obtained by an apheresis procedure. Granulocytes are considered for patients with severe neutropenia with life-threatening bacterial or fungal infection not responsive to antibiotic therapy.
Fresh Frozen Plasma (FFP)-is the plasma removed from a unit of whole blood and frozen at or below 55° Fahrenheit within eight hours of collection. FFP contains all coagulation factors in normal amounts and is free of red cells, leukocytes and platelets. It is indicated for patients with coagulation factor deficiencies.
Cryoprecipitate (CRYO)-is a concentrate of three hemostatic proteins prepared from donated whole blood. A single bag of Cryo contains an average of 100 units of factor VIII and von Willebrand factor and 150 to 250 mg of fibrinogen with some factor XIII and fibronectin. No compatibility testing is required and ABO-Rh type is not relevant. It is indicated for bleeding or imminent invasive procedures for patients with significant hypofibrinogenemia.
Factor VIII Concentrates-Factor VIII concentrates are a commercially prepared, lyophilized powder purified from human plasma to treat patients with hemophilia A or von Willebrand’s disease.
Antithrombin III-Antithrombin III concentrates are commercially purified from human plasma pools and lyophilized.
Below is a list of some abbreviations used frequently in relation to hematological diseases, blood, blood products and blood transfusion.
Abbr. Form Full meaning
ACT Activated Clotting Time
ADH Antidiuretic Hormone
AHG Antihuman Globulin
AIDS Acquired Immune Deficiency Syndrome
ALT Alanine Aminotransferase
ANA Antinuclear Antibody
ANH Acute Normovolemic Hemodilution
anti-HBc Antibody to Hepatitis B Core Antigen
anti-HCV Antibody to Hepatitis C Virus
anti-HTLV-I/II Antibody to Human T-cell lymphotropic virus type I/II
aPPT Activated Partial Thromboplastin Time
ARDS Acute Respiratory Distress Syndrome
AST Aspartate Transaminase
CHD Coronary Heart Disease
CPD Citrate, Phosphate, Dextrose solution
CPDA-1 Citrate, Phosphate, Dextrose-Adenine solution
C/T Crossmatch-to-Transfusion ratio (C:T)
DDAVP 1-Desamino-8-D-Arginine Vasopressin
DIC Disseminated Intravascular Coagulopathy
EACA epsilon-aminocaproic Acid
FDA Food and Drug Administration
FFP Fresh Frozen Plasma
FNHTR Febrile Nonhemolytic Transfusion Reaction
GGTP Gamma Glutamyl Transferase (GGT)
GHVD graft-versus-host Disease
HAM HTLV-1-associated Myelopathy
HBsAg Hepatitis B Surface Antigen
HBV Hepatitis B Virus
HCV Hepatitis C Virus
HDN Hemolytic Disease of the Newborn
HH Hemochromatosis (distinguish from H&H)
HIV Human Immunodeficiency Virus
HLA Human Leukocyte Antigen
HTLV-I/II Human T-cell Lymphotropic Virus type I/II
IAD Intraoperative Autologous Donation
IgA Immunoglobulin A
ITP Idiopathic Thrombocytopenic Purpura
LD Lactate Dehydrogenase
MCH Mean Corpuscular Hemoglobin
MCHC Mean Corpuscular Hemoglobin Concentrate
MCV Mean Corpuscular Volume
mg/dL milligrams per deciliter
MPV Mean Platelet Volume
PPF Purified Protein Fraction
PRP platelet-rich Plasma
PT Prothrombin Time
PTP Posttransfusion Purpura
PTT Partial Thromboplastin Time
RBCs Red Blood Cells
Rh Rhesus Factor
STS Serological Test for Syphilis
T&S Type and Screen
TA-GVHD transfusion-associated graft-versus-host disease
TSH Thyroid Stimulating Hormone
TSP Tropical Spastic Paraparesis
TSE Transmissible Spongiform Encephalopathies
TTP Thrombotic Thrombocytopenic Purpura
TTTS Twin to Twin Transfusion Syndrome
WBCs White Blood Cells
vWd von Willebrand's Disease
vWf von Willebrand's Factor
Blood donation is a process by which a blood donor voluntarily has blood drawn for storage in a blood bank or for subsequent use in a blood transfusion.
To understand the importance of the availability of a sustainable donated blood supply, the catch-cry of the Australian Red Cross Blood Service is, "80% of Australians will need blood in their lifetime, but less than 3% of Australians give blood each year." In the United States, the odds of knowing someone who will need blood are "97%", according to that branch of the Red Cross. According to polling conducted by Canadian Blood Services, 52% of Canadians have needed blood or know someone who has.
Why donate blood?
There is tremendous demand for blood in hospitals. Many patients die because they are not able to cope with the loss of blood.
Blood donated is used to:
Replace blood lost during injury as in accidents.
Replace blood loss during major surgeries.
Help patients with blood disorders like hemophilia, Von Willebrand’s disease survive.
Help burns patients receive plasma, that may be critical for their survival.
Raise hemoglobin levels ( through transfusions) in patients with chronic ailments like kidney diseases, cancer and anaemia.
Blood donation hardly makes a difference in terms of health to the donor, but it can help save the life of a patient.
Who can donate blood?
Some basic health conditions have to be met by donors:
A donor should:
Be above 18 years and below 60 years of age.
Have a hemoglobin count that is not less than 12.5 g/dl
Weigh not less than 45 kgs.
Have normal body temperature at the time of donation.
Have normal BP at the time of donation.
Should be free of any disease at the time of donation.
Who should not donate blood?
The following categories of people should avoid giving blood:
Pregnant or lactating women, or those who have recently had an abortion.
Persons who are on steroids, hormonal supplements or certain specified medication.
Persons with multiple sexual partners or those who are addicted to drugs.
Persons who have had an attack of infection like jaundice, rubella, typhoid or malaria.
Persons who have undergone surgery in the previous six months.
Persons who have consumed alcohol in the 24 hours prior to donation.
Women should avoid donation during their menstruating period.
Those who have undergone various vaccinations should avoid donation for the corresponding period specified below:
Type of Vaccine: The period in which donation should be avoided.
Hepatitis B 6 months
Live vaccines 2 weeks
Killed vaccines 48 Hours
Rabies 1 year
§ Persons with any systemic disease like heart disease, kidney disease, liver problems, blood disorders or asthma should NOT donate blood.
§ Persons suffering from infections transmitted through transfusions like HIV, Hepatitis, Syphilis etc should Not donate blood.
How much blood is taken at the time of donation? How soon does the body make good this loss?
Only 350 ml of blood is taken at the time of donation. An average person has 5-6 liters of blood in the body.
In terms of volume, the loss is corrected in 24-48 hours by the body. The red cell count is corrected in about 56 days.
How long does the process of donation take?
The actual bleeding time is about 5-6 minutes. There is a medical check up before this and rest is advised (for 5-10 minutes) and usually accompanied with some refreshment after donation. The whole process takes about 30 minutes.
How often can one donate blood?
The minimum time advised between two donations is 3 months. This gap helps blood regain the normal hemoglobin count.
Are there any hazards in blood donation? What are the precautions that need to be taken?
Health does not suffer because of the blood donated. In fact, the bone marrow is stimulated to produce new cells.
However, if conditions are not hygienic, one may be exposed to infection. Hence, it is necessary to use sterile procedures and disposable needles.
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Blood - Function and Products