<< Chapter < Page Chapter >> Page >

Erythroblastosis fetalis

This figure shows an umbilical artery and vein passing through the placenta on the top left. The top right panel shows the first exposure to Rh+ antibodies in the mother. The bottom right panel shows the response when the second exposure in the form of another fetus takes place. Textboxes detail the steps in each process.
The first exposure of an Rh mother to Rh + erythrocytes during pregnancy induces sensitization. Anti-Rh antibodies begin to circulate in the mother’s bloodstream. A second exposure occurs with a subsequent pregnancy with an Rh + fetus in the uterus. Maternal anti-Rh antibodies may cross the placenta and enter the fetal bloodstream, causing agglutination and hemolysis of fetal erythrocytes.

A drug known as RhoGAM, short for Rh immune globulin, can temporarily prevent the development of Rh antibodies in the Rh mother, thereby averting this potentially serious disease for the fetus. RhoGAM antibodies destroy any fetal Rh + erythrocytes that may cross the placental barrier. RhoGAM is normally administered to Rh mothers during weeks 26−28 of pregnancy and within 72 hours following birth. It has proven remarkably effective in decreasing the incidence of HDN. Earlier we noted that the incidence of HDN in an Rh + subsequent pregnancy to an Rh mother is about 13–14 percent without preventive treatment. Since the introduction of RhoGAM in 1968, the incidence has dropped to about 0.1 percent in the United States.

Determining abo blood types

Clinicians are able to determine a patient’s blood type quickly and easily using commercially prepared antibodies. An unknown blood sample is allocated into separate wells. Into one well a small amount of anti-A antibody is added, and to another a small amount of anti-B antibody. If the antigen is present, the antibodies will cause visible agglutination of the cells ( [link] ). The blood should also be tested for Rh antibodies.

Cross matching blood types

This figure shows three different red blood cells with different blood types.
This sample of a commercially produced “bedside” card enables quick typing of both a recipient’s and donor’s blood before transfusion. The card contains three reaction sites or wells. One is coated with an anti-A antibody, one with an anti-B antibody, and one with an anti-D antibody (tests for the presence of Rh factor D). Mixing a drop of blood and saline into each well enables the blood to interact with a preparation of type-specific antibodies, also called anti-seras. Agglutination of RBCs in a given site indicates a positive identification of the blood antigens, in this case A and Rh antigens for blood type A + . For the purpose of transfusion, the donor’s and recipient’s blood types must match.

Abo transfusion protocols

To avoid transfusion reactions, it is best to transfuse only matching blood types; that is, a type B + recipient should ideally receive blood only from a type B + donor and so on. That said, in emergency situations, when acute hemorrhage threatens the patient’s life, there may not be time for cross matching to identify blood type. In these cases, blood from a universal donor    —an individual with type O blood—may be transfused. Recall that type O erythrocytes do not display A or B antigens. Thus, anti-A or anti-B antibodies that might be circulating in the patient’s blood plasma will not encounter any erythrocyte surface antigens on the donated blood and therefore will not be provoked into a response. One problem with this designation of universal donor is if the O individual had prior exposure to Rh antigen, Rh antibodies may be present in the donated blood. Also, introducing type O blood into an individual with type A, B, or AB blood will nevertheless introduce antibodies against both A and B antigens, as these are always circulating in the type O blood plasma. This may cause problems for the recipient, but because the volume of blood transfused is much lower than the volume of the patient’s own blood, the adverse effects of the relatively few infused plasma antibodies are typically limited. Rh factor also plays a role. If Rh individuals receiving blood have had prior exposure to Rh antigen, antibodies for this antigen may be present in the blood and trigger agglutination to some degree. Although it is always preferable to cross match a patient’s blood before transfusing, in a true life-threatening emergency situation, this is not always possible, and these procedures may be implemented.

A patient with blood type AB + is known as the universal recipient    . This patient can theoretically receive any type of blood, because the patient’s own blood—having both A and B antigens on the erythrocyte surface—does not produce anti-A or anti-B antibodies. In addition, an Rh + patient can receive both Rh + and Rh blood. However, keep in mind that the donor’s blood will contain circulating antibodies, again with possible negative implications. [link] summarizes the blood types and compatibilities.

At the scene of multiple-vehicle accidents, military engagements, and natural or human-caused disasters, many victims may suffer simultaneously from acute hemorrhage, yet type O blood may not be immediately available. In these circumstances, medics may at least try to replace some of the volume of blood that has been lost. This is done by intravenous administration of a saline solution that provides fluids and electrolytes in proportions equivalent to those of normal blood plasma. Research is ongoing to develop a safe and effective artificial blood that would carry out the oxygen-carrying function of blood without the RBCs, enabling transfusions in the field without concern for incompatibility. These blood substitutes normally contain hemoglobin- as well as perfluorocarbon-based oxygen carriers.

Abo blood group

This table shows the different blood types, the antibodies in plasma, the antigens in the red blood cell, and the blood compatible blood types in an emergency.
This chart summarizes the characteristics of the blood types in the ABO blood group. See the text for more on the concept of a universal donor or recipient.

Chapter review

Antigens are nonself molecules, usually large proteins, which provoke an immune response. In transfusion reactions, antibodies attach to antigens on the surfaces of erythrocytes and cause agglutination and hemolysis. ABO blood group antigens are designated A and B. People with type A blood have A antigens on their erythrocytes, whereas those with type B blood have B antigens. Those with AB blood have both A and B antigens, and those with type O blood have neither A nor B antigens. The blood plasma contains preformed antibodies against the antigens not present on a person’s erythrocytes.

A second group of blood antigens is the Rh group, the most important of which is Rh D. People with Rh blood do not have this antigen on their erythrocytes, whereas those who are Rh + do. About 85 percent of Americans are Rh + . When a woman who is Rh becomes pregnant with an Rh + fetus, her body may begin to produce anti-Rh antibodies. If she subsequently becomes pregnant with a second Rh + fetus and is not treated preventively with RhoGAM, the fetus will be at risk for an antigen-antibody reaction, including agglutination and hemolysis. This is known as hemolytic disease of the newborn.

Cross matching to determine blood type is necessary before transfusing blood, unless the patient is experiencing hemorrhage that is an immediate threat to life, in which case type O blood may be transfused.


American Red Cross (US). Blood types [Internet]. c2013 [cited 2013 Apr 3]. Available from: (External Link) 2013

Questions & Answers

structure of the cell
what do u want to know about the structure of the cell?
Process of bone healing
Thelma Reply
The fractured bones are brought closer (reduction of fracture). the fibroblast cells at broken ends divide rapidly and secrete collagen that forms collar of callus. The callus holds the bones together which slowly clacifies (remodelling) and later replaced by bone tissue.
what is the name of the two subunits of L chain of a antibody structure
Arshi Reply
The pituitary gland lies in the
Aamir Reply
bony cavity,sella tursica
how does endochrondral ossification start in short bones?
Steven Reply
the chondroblast cells forms a cartilaginous bone model which becomes calcified in mid region and is innervated by perosteal capillaries. These capillaris replaces cartilages with bone tissue.
define negative feedback
mechanism that cause supression of another process. eg. the secretion of one hormone can supress the other hormone secretion.
simply a self regulating mechanism which retun a deviated parameter to normal condition
secretion of hormones get supressed by other hormone secretion
by like 😂😂😂😂
what is RH blood group
kuukyile Reply
It is a type of system for classifying blood groups according to the presence or absence of the Rh antigen.
What is the most important organ in the human body?
Gbemi Reply
the heart
or brain
the brain specifically is referred to as the control centre ..all nerve impulses are send to the brain which stimulates other specific parts of the body
please if l am Blood group B+ can l marry a lady with O- blood group?
structure of a serous membrane
Ziyanda Reply
are you asking?
In anatomy, serous membrane (or serosa) is a smooth tissue membrane consisting of two layers of mesothelium, which secrete serous fluid. The inner layer that covers organs (viscera) in body cavities is called the visceral membrane. A second layer of epithelial cells of the serous membrane, called th
The two layers of serous membranes are named parietal and visceral. Between the two layers is a thin fluid filled space.[2] The fluid is produced by the serous membranes and stays between the two layers to reduce friction between the walls of the cavities and the internal organs when they move with
a continuation from the 1st one:: A second layer of epithelial cells of the serous membrane, called the parietal layer, lines the body wall. Between the two layers is a potential space, mostly empty except for a few milliliters of lubricating serous fluid that is secreted by the two serous membranes
Lubricated secretion of skin is called sebum
what is the greater tronchanter?
the greater trochanter is  femur is a large, irregular, quadrilateral eminence and a is a part of the system of the skeleton
Thanks Jessie...
what is the easiest way to learn labels of Anatomical structures?
what's the anatomical plan of the horse lung
Name the two phases of metabolism
Grace Reply
reproduction and growth
how about anabolism and catabolism?
In Simply Anabolism means formation... Catabolism means breakdown
two phases of reproductio?
Anabolism indicates potential & catabolism potential converts to kinetic
Name the most important life process in the human body in terms of anatomy and physiology
Nervous system
Every system is important for body functions
what is the difference between the functions of the adhesion belt and the desmosomes?
Mason Reply
what are the derivatives of the germ layer?
Miriam Reply
Pls explain the atlas of the cervical vertebral column
Ifunanya Reply
why does the material not allow in mri
Simran Reply
what do you mean 'mri'
short for magnetic resonance imaging. "the researchers used MRI to record the brain activity" a medical examination performed using magnetic resonance imaging. "he's having an MRI to determine the extent of the injury" an image obtained by magnetic resonance imaging. "after looking at the MRI, the d
what is the meaning of sutures
Ibrahim Reply
i do not know
immovable joints btn two bones.eg the skull bones
Really,it's true
Sutures are immovable junction between two bones e.g those of the skull
what should I do to get or to know what to do for me to be excellent in the course of anatomy and physiology
Sandra Reply
study harder

Get the best Anatomy & Physiology course in your pocket!

Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Anatomy & Physiology' conversation and receive update notifications?