Abo blood groups

The ABO blood grouping is a system of classifying the blood groups based on a persons antigens which determine their antibodies, and compatibility to receive blood. The ABO blood grouping system to be the most important blood type system for human blood transfusion.

Common Blood Groups

The ABO group is classified based on the antigen. If a person is blood group A, that means they have antigen type called A. This also means that they will have antibodies to the non-A (read B) type blood groups. To understand the ABO blood group system, look at the following table.

ABO Group	Blood Type	Antigen A	Antigen B	Anti A antibody	Anti B antibody
A		yes	no		no	yes
B		no	yes		yes	no
O		no	no		yes	yes
AB		yes	yes		no	no

In the above table, in column 1, the person with group A blood has antigens to A, so they cannot have antibodies to A, but will have antibodies to B.

In order to prevent certain diseases that are transmitted by blood, screening is not only recommended but mandatory.

Screening blood donors

Blood donors are commonly asked a set of questions and if the donor’s answers indicate they are not well or are at risk for having a disease transmissible by blood transfusion, they are not allowed to donate blood. If the screening questions were answered and the person was able to donate, the second step is to screen the donated blood is tested for blood type (ABO group) and Rh type (positive or negative) in order to make sure that patients receive blood that matches their blood type. Also, all donated blood is to be tested for evidence of certain infectious disease pathogens including hepatitis B and hepatitis C viruses and human immunodeficiency virus (HIV).

Infectious Disease Pathogen	Laboratory Tests Used
Bacterial Contamination	Bacterial culture
Hepatitis B virus (HBV)	"Hepatitis B surface antigen (HBsAg) detection
Hepatitis B core antibody (anti-HBc) detection"
Hepatitis C virus (HCV)	"Hepatitis C virus antibody (anti-HCV) detection
Nucleic acid amplification testing (NAT) for HCV"
Human Immunodeficiency virus Types 1 and 2 (HIV)	"HIV-1 and HIV-2 antibody (anti-HIV-1 and anti-HIV-2) detection
Nucleic acid amplification testing (NAT) for HIV-1"
Human T-Lymphotropic Virus Types I and II (HTLV)	HTLV-I and HTLV-II antibody (anti-HTLV-I and anti-HTLV-II) detection
Treponema pallidum (syphilis)	Anti-treponemal antibody detection
West Nile virus (WNV)	Nucleic acid amplification testing (NAT) for WNV

Adverse Reactions Associated with Blood Transfusions

The possibility of having a answer to a blood transfusion is very little. The most widespread adverse reactions from blood transfusions are allergic and febrile (fever–associated) reactions, which make up over half of all adverse reactions described. uncommon but grave adverse reactions encompass infection caused by bacterial contamination of blood goods and immune reactions due to difficulties in blood type matching between donor and recipient.

The following is a register of blood transfusion-associated harmful reactions that are followed through the National Healthcare security Network (NHSN) Hemovigilance Module. These harmful reactions are not widespread following blood transfusions but are followed so that CDC can better understand them and evolve interventions to avert them.

Allergic reaction to blood transfusion

An allergic reaction results from an interaction of an allergen in the transfused blood with preformed antibodies in the person obtaining the blood transfusion. In some examples, infusion of antibodies from the donor may be engaged. The answer may present only with irritation of the skin and/or mucous membranes but can furthermore involve serious symptoms such as adversity respiring.

Acute hemolytic transfusion reaction (AHTR)

An acute hemolytic transfusion reaction is the fast decimation of red blood cells that occurs throughout, directly after, or within 24 hours of a transfusion when a persevering is granted an incompatible blood kind. The recipient’s body directly starts to decimate the pledged red blood units resulting in fever, agony, and sometimes critical complications such as kidney malfunction.

Delayed hemolytic transfusion answer (DHTR)

A delayed hemolytic transfusion answer happens when the recipient evolves antibodies to red blood cell antigen(s) between 24 hours and 28 days after a transfusion. Symptoms are generally milder than in acute hemolytic transfusion reactions and may even be missing. DHTR is diagnosed with laboratory checking.

Delayed serologic transfusion reaction (DSTR)

A delayed serologic transfusion answer happens when a recipient evolves new antibodies against red blood units between 24 hours and 28 days after a transfusion without clinical symptoms or lab evidence of hemolysis. Clinical symptoms are rarely associated with DSTR

Febrile non-hemolytic transfusion answer (FNHTR)

Febrile non-hemolytic transfusion answers are the most widespread answer described after a transfusion. FNHTR is distinuished by fever and/or chills in the nonattendance of hemolysis (breakdown of red blood units) occurring in the patient throughout or up to 4 hours after a transfusion. These reactions are usually gentle and reply quickly to remedy. high temperature can be a symptom of a more critical answer with more serious determinants, and should be completely investigated.

Hypotensive transfusion answer

A hypotensive transfusion answer is a drop in systolic blood force happening shortly after a transfusion begins that answers rapidly to cessation of the transfusion and supportive remedy. Hypotension also can be a symptom of a more severe answer and should be fully enquired.

Post-transfusion purpura (PTP)

Post-transfusion purpura is a uncommon but possibly fatal status that occurs when a transfusion recipient develops antibodies against platelets, producing in fast destruction of both transfused and the patient’s own platelets and a severe decline in the platelet enumerate. PTP usually happens 5-12 days after a transfusion and is more common in women than in men.

Transfusion-associated circulatory overload (TACO)

Transfusion-associated circulatory overload happens when the volume of blood or blood components are transfused will not be effectively processed by the recipient. TACO can occur due to an excessively high injection rate and/or volume or due to an underlying heart or kidney condition. Symptoms may encompass adversity respiring, hack, and fluid in the lungs.

Transfusion-related acute lung injury (TRALI)

Transfusion-related acute lung injury is a serious but rare answer that happens when fluid builds up in the lungs, but is not related to excessive capacity of blood or blood products transfused. Symptoms encompass acute respiratory distress with no other interpretation for lung injury such as pneumonia or trauma occurring inside 6 hours of transfusion. TRALI is a leading origin of transfusion-related death described to the FDA. The mechanism of TRALI is not well appreciated, but is considered to be associated with the presence of antibodies in donor body-fluid.

Transfusion-associated dyspnea (TAD)

Transfusion associated dyspnea is the onset of respiratory anguish inside 24 hours of transfusion that will not be characterised as TACO, TRALI, or an allergic answer.

Transfusion-associated graft vs. host infection (TAGVHD)

Transfusion-associated graft vs. host infection is a rare difficulty of transfusion that happens when donor T-lymphocytes (the “graft”) presented by the blood transfusion quickly increase in number in the recipient (the “host”) and then attack the recipient’s own cells. Symptoms include high temperature, a attribute rash, enlargement of the liver, and diarrhea that happen between 2 days and 6 weeks mail transfusion. Though very uncommon, this inflammatory answer is tough to heal and often outcomes in death.

Transfusion-transmitted infection (TTI)

A transfusion-transmitted infection happens when a bacterium, parasite, virus, or other potential pathogen is conveyed in pledged blood to the transfusion recipient.

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