Paroxsymal Cold Hemoglobinuria (PCH)

What is PCH?

        Autoantibody (Biphasic hemolysin) that binds to Red Blood Cells after the exposure to the Cold, and then the Red Blood Cells lyse and release Hemoglobin when body is warmed back up to body temperature.

Clinical Presentation:

         Recurrence of a fever and Dark urine 1-2 weeks after a Urinary Tract Infection (UTI)

         Can occur after the exposure to the Cold

         Hemolysis is usually acute and severe

              Hemoglobin < 5 g/dl

 

         Symptoms:

              Fever

              Abdominal Pain

              Hepatosplenomegaly (Enlarged Liver and Spleen)

              Fatigue

              Hemoglobinuria (dark urine; hemoglobin in the urine)

              Pallor

              Jaundice

 

Occurence:

    Occurs more often in children after viral infection but spontaneously resolves.

                Adults are more chronic, but not as severe

 

Diagnosis:

               Identification of symptoms and lab values

               Diagnostic Lab Test: Donath-Landsteiner Test

                            Patient plasma and Cells are incubated at Cold and Warm Temperatures.

                                             If Hemolysis appears in the tubes incubated first at 4C and then at 37C and not in the other tubes, it is Positive.

 

Antibody Specificity:

              The autoantibody is usually IgG with anti-P specificity and is a biphasic hemolysin.

 

Treatment:

             Supportive Therapy through blood transfusion and medications

ANTI-G

The G antigen is present on all RBCs that are D and/or C positive
            rare exception is the  rG cell
                       D and C negative but G positive

Why do we care about the G antigen and its antibody?
           When someone has anti-G it looks like they have antibodies to both D and C antigen
           Generally, you'd transfuse these patients with D negative and C negative blood which so happens to be G negative. So why do we care? If an obstetric patient has anti-G as opposed to anti-D + anti-C they do not have as severe Hemolytic Disease of the Newborn (HDN), but could make anti-D that would cause a severe form of HDN, so RhIg would be indicated.

       How do you know if it is anti-G or anti-D + anti-C?
                  Most reference labs will perform adsorption and elution studies to try to differentiate the two.
                        You'd utilize a D-C+G+ cell and incubate it with the patient's plasma. If anti-G is only present it will be removed from the plasma onto the cell, so when you elute the antibody you will find your eluate will react with both D+C- and D-C+ cells.
                                                 If it is anti-D + anti-C, your eluate will only react with the D-C+ cells.

Red Blood Cell Transfusion

Indications:
        Treatment of anemia in cases too severe to be treated by nutritional replacement or iron
        Loss of 10-15% of total blood volume during surgery
        Correction of perioperative anemia
        Hypotension associated with bleeding

The Transfusion Trigger:
           Generally is having a hemoglobin of 7 g/dl or less.
           If the patient has cardiac problems it is set at 10 g/dl

Why is having a low Hemoglobin and being anemic harmful?
           Hemoglobin transports Oxygen from the lungs to the tissues
           And transports Carbon dioxide from the tissues to the lungs
           Without enough hemoglobin the tissues do not get enough Oxygen and their is a build up of Carbon dioxide. This causes the tissues to become hypoxic and will begin to die. 

How does the body compensate for low hemoglobin levels?
         When hemoglobin levels get below 7 g/dl the heart starts to beat faster to pump blood through the body at a faster rate since their is less blood in the body.
                     This is why those patients with heart problems need to have a transfusion trigger that is higher (like 10 g/dl) because their heart cannot compensate.
          The tissues have a stronger affinity for Oxygen and will grab more of it as the Hemoglobin molecule passes by.

The risk of death from anemia is when the hemoglobin level reaches 3 g/dl. The body cannot compensate for the lack of oxygen and the body begins to shut down. Prolonged levels of a Hemoglobin of 3 or less usually results in death.

Red Blood Cell (RBCs) Transfusions:
        One unit of RBCs can increase the Hemoglobin by 1 g/dl and can be life saving in patients with severe anemia or bleeding.

What is a Type & Screen?

Do you know what testing is done on your blood when a doctor orders a type and screen?
     It is actually two tests:
          The Type:
              Determine your ABO and Rh type
                      Look for the A or B antigen on the Red Blood Cell and for anti-A or anti-B in the plasma
                                     This determines your ABO type
                     Look for the D antigen on the Red Blood Cell
                                     This determines if you are Rh positive or negative

         The Screen:
              Look for antibodies to Red Blood Cell antigens that have developed due to exposure to foreign Red Blood Cells through transfusion, pregnancy, or sharing of blood via needles.
              It is interpreted as either Positive or Negative
                      For Positive Antibody Screens, the antibody is identified and future blood transfusions should not have the Red Blood Cell antigen to the identified antibody.


What is meant by Type & Cross?
        This means that the doctor wants the lab to perform a Type & Screen, plus crossmatch Red Blood Cell untis for transfusion.

RhIg

What is RhIg?
      It a blood derivative that is used to prevent the formation of antibodies to the D antigen in Rh negative persons. Brand name is Rhogam.

Why is it important?
     Prior to the development of RhIg in the 1970s, fetal loss due to anti-D was as high as 46 in 100,000 pregnancies; now it causes 1.6 in 100,000. The D antigen is present in >85% of people and is highly immunogenic. The antibody that forms (anti-D) in a Rh negative person is IgG and can cross the placenta and destroy Rh positive fetal cells causing fetal anemia and/or death.

When is it administered?
    RhIg is given at to Rh negaitve pregnant women at 28 weeks gestation and within 72 hours after delivery.
    Or given to children or women of child-bearing age (< 50 years old) after receiveing Rh positive Red Blood Cells or Platelets.

Why is it administered?
    Since the D antigen is so immunogenic, as little as 2 ml of D positive blood can cause the formation of anti-D. There is the risk during pregnancy to have a fetal maternal bleed which would expose mom to fetal blood and develop this antibody, risks are highest after 28 weeks and at birth.

How does RhIg work?
    RhIg is an passive anti-D that binds to any D positive cells and those cells are then removed by the spleen. This prevents the person's body from recognizing it and making their own anti-D which lasts forever and may compromise future pregnancies. The RhIg generally is gone from the person's system in 3 months.

How much is given?
    One does is considered sufficient for the 28 week dose, but the risk of fetal bleed is greater during birth so another test, Fetal Maternal Hemorrhage Screen, must be performed to determine if more than one dose of RhIg is warranted.

Who is eligible to receive RhIg?
     Person must be Rh negative
     Person must not already have anti-D
     Must be exposed to Rh positive blood (from fetus or blood transfusion)

Are there other ways besides pregnancy and blood transfusion that one can develop Red Cell antibodies?
    Yes. There has been some evidence that sharing needles can expose persons to other peoples blood and potentially make antibodies.

Does RhIg prevent all cases of Fetal anemia due to antibody?
    No. There are many antigens on the Red Blood Cells and if antibodies to these are formed it can cause fetal anemia and/or death. Anti-D is just the most common one. There are no other products currently available to prevent these antibodies from forming.


Rhogam package insert

Medical Ethics Related to Blood Banking

Bioethics
  -  Moral conduct of the right and wrong in life and death issues.

Guidelines for confronting bioethical dilemmas.

                        Principle of Autonomy
                        People have the right to make decisions about their own life
            Principle of Beneficence
                        Do good
            Principle of Nonmaleficence
                        “First, Do no Harm”
            Justice
                        Treat everyone equally

Bioethical Issues
        Protecting human subjects in clinical trials
           Affordability
           Privacy
           Stem Cell Research
           Defending the United States against terrorism
           Organ and Tissue Procurement and allocation

Blood Bank related lawsuits on Bioethical Issues
          Transfusion Transmission of HIV/AIDS
          Informed Consent (Donor and Recipient)
          Untimely notification of positive test results
          Failure to offer Directed Donation services
          Failure of test performance

Other Ethical Issues about personal choice in healthcare
          Religion
               Jehovah's Witnesses generally refuse blood transfusion
          Euthanasia
          Fertility drugs and multiple births

Ethical Code of Conduct for Laboratory Professionals
     American Society of Clinical Laboratory Science (ASCLS) code of ethics

Prevention of Transfusion Transmitted Disease

A big concern with blood safety revolves around infectious disease transmission. Today, with our advances in testing the risk of acquiring HIV/AIDS from a blood transfusion is 1 in 2 million transfusions. Hepatitis C(HCV) is also a concern with a risk of 1 in 2 million transfusions. The biggest transfusion transmitted risk is bacterial transmission from Staphylococcus sp. with a risk of 1 in 500,000 in RBCs and 1 in 50,000 for platelets. Prevention of Transfusion Transmitted Disease is accomplished using a detailed Donor History Questionnaire (DHQ) and Infectious Disease Testing.

Infectious Disease Tesing is required on all transfused Blood products and they are the following:
     Hepatitis B surface Antigen (HBsAg)
     antibody to Hepatitis B core (anti-HBc)
     antibody to Hepatitis C (anti-HCV)
     Hepatitis C RNA (HCV RNA) - Nucleic acid testing (NAT)
     antibody to HIV-1/2 (anti-HIV-1/2)
     HIV-1 RNA (NAT)
     antibodies to HTLV-I/II (anti-HTLV-I/II)
     West Nile virus RNA (WNV RNA) (NAT)
      serologic test for syphilis

  Platelets are also tested for bacterial contamination

NAT is able to amplify and detect genetic sequences of a virus, so that those infected with these viruses are detected earlier (some within 10 days after exposure) to prevent transmission.
    

ABO Blood Group

The ABO Blood Group System was discovered in 1900 by Landsteiner and is the most important Blood Group System.

There are 4 different ABO Blood Types: A, B, AB, and O

The gene for the H antigen is locared on Chromosome 19 and encodes for L-fucosyltransferase.
      This enzyme places Fucose onto precursor chains on the RBC and on precursor chains in secretions (urine, saliva, plasma, etc).

The genes for the A and B antigens is locared on Chromosome 9 and there are two co-dominant alleles, A and B.
       The B allele encodes for D-galactosyltransferase
       The A allele encodes for N-acetylgalactosaminyl transferase

These enzymes added a sugar onto the Fucose that was added by the H gene.

              ABO type of a person is determined by these sugars on the RBC
                    A - N-acetylgalactosamine
                    B - D-galactose
                    AB - both N-acetylgalactosamine and D-galactose
                    O - no sugar is added

The ABO blood group system is unique as it is the only one that the body will form antibodies to the antigens. For example, if you are an A you will have antibodies to B. This is why the blood group system is so important. If you were to transfuse B RBCs to an A person, they would destroy them and cause catastrophic problems for the body that may include death. The Blood Banks most important test is to determine the ABO type of recipients and blood donors to ensure that this does not happen.

ABO typing consists of performing an antigen typing of the RBCs (look for the A and/or B antigen) and the reverse typing (look for anti-A and/or anti-B in the plasma). This is how a person's ABO blood type is determined.


ABO type         ABO Antigen Typing             ABO reverse typing

      A                        A antigen present               anti-B present

      B                         B antigen present               anti-A present

     AB           A and B antigen present             No ABO antibodies present

       O           No A or B antigens present        anti-A & anti-B present

Picture of the reagents for ABO typing.

Blood Components

Whole Blood:
      Contains all blood elements plus anticoagulant-preservative

      Used to increase oxygen carrying capacity and volume expansion in massively bleeding patients.

      Storage: 1-6° C for up to 35 days

Red Blood Cells (RBCs):

      Prepared from whole blood after removal of plasma or collected using an apheresis machine(2 unit).

      Used to increase oxygen carrying capacity           

      Storage: 1-6°C for up to 42 days

Fresh Frozen Plasma (FFP):
     Prepared from whole blood or using an apheresis machine.
     Used to treat patients with multiple coagulation factor deficiency who are bleeding or who will be undergoing an invasive procedure.

            Contains maximum levels of labile (Factor V and VIII) and no labile clotting factors.
     Storage: Frozen <-18°C for up to 12 months

                  Thawed at 30-37°C and stored at 1-6°C for up to 24 hours

Platelets:

     Prepared from whole blood (not <20°C) within 4 hrs or by using an apheresis machine.

                   Used of thrombocytopenia in bleeding patients (<50,000/ml)

                   Storage: 20-24°C with agitation for up to 5 days

Cryoprecipitate:

       Prepared from the insoluble portion of FFP when it is hawed at 1-6°C, and is refrozen within 1 hr of preparation.

       Used to treat fibrinogen deficiency or Factor XIII deficiency.

       Contains High levels of fibrinogen, Factor VIII and XIII and is suspended in 15ml of plasma

       Storage: Frozen <-18°C for up to 12 months

                    Thawed at 20-24°C for up to 6 hours

Granulocytes:

       Prepared from whole blood or apheresis (mostly apheresis).

            Can be harvested in buffy coats (UK)

       Used when patient has an infection, neutropenia, a failure to respond to antibiotics, myeloid hypoplasia, and a reasonable chance of recovery.

       Transfuse as soon as possible after collection

       Storage: 20-24°C with no agitation for up to 24 hours

  

Governing Bodies

The Blood Bank is a high regulated industry that is monitored and inspected by many different organizations.

Regulatory Agencies:
    These agencies enforce Federal Law and can shut down a hospital or lab if these regulations are violated.

       Food & Drug Administration (FDA)
          Provide Code of Federal Regulations (CFR) that are rules written and enforced by the Federal Government
          Provide current Good Manufacturing Practices (cGMP) which gives guidance on production of drugs and biologics to ensure safety, purity, and potency.
          The FDA can inspect any facility unannounced.

      Centers for Medicare & Medicaid Services (CMS)
          Provide CMS regulations for the protection of patients and donors, which includes Civil Rights and Privacy Laws related to health care and research.
        
Accrediting Agencies:
      These agencies set standards that must be met by the hospital or lab to attain and maintain accreditation. These agencies do routine unannounced inspections of accreditated facilities.

           Joint Commission on Accreditation Of Healthcare Organizations (JCAHO)
           College of American Pathologists (CAP)
          Advancing Transfusion and Cellular Therapies Worldwide  (AABB)

Laboratory Specific Laws:
      Clinical Laboratory Improvement Act of 1988 (CLIA '88), in 1988 the Congress decided that their needed to regulate all the labs in the US. Explanation of CLIA '88 .
   
Other agencies that regulate the Blood Bank:  

      Occupational Health & Safety Administration (OSHA)
          Provides and enforces regulations to provide safe and healthful working conditions.
                They require employers to provide safety training of personnel,  personal protective equipment (PPE), vaccinations, and follow-up care for any exposures to hazardous material.

     Department of Transportation (DOT)
          U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) provides a guidance document to ensure safe shipping of blood products.
      
      Nuclear Regulatory Commission (NRC) regulates how nuclear material is used in the U.S. and how it is protected from misuse. Hospitals, Blood Banks, and Donor Centers having access to radioactive material for manipulation of Blood Products must follow these regulations.
         

Blood Donor Selection - Physical Exam

Not just anyone can be a Blood Donor. There is a specific process that must be followed to ensure a safe donation for the donor and a safe product for the recipient. The following are the physical requirements for allogeneic donation.

Physical Exam:
     Appear to be in Good Health
     Weight: > 110 lbs (to ensure donor can tolerate donating 500ml of blood)
     Temperature: < 37.5 C or 99.5 F (to ensure there is not an underlying infection)
     Pulse: 50-100 beats per minute (<50 is acceptablefor athletes) (to ensure no underlying cardiac problem that donor cannot tolerate blood donation)
     Blood Pressure: <180/100 mm Hg (to ensure no underlying cardiac problem that donor cannot tolerate blood donation)
     Hemoglobin: > 12.5 g/dL      or     Hematocrit >38%       or      Specific Gravity with Copper Sulfate >1.053
      Venipuncture site must be free of skin lesions (to prevent contamination of blood donation or identify drug use)

   If a donor does not meet these criteria they will deferred from the current donation but can attempt again at a later time.


    
    

The Blood Bank

The Blood Bank is a special part of the lab that not only performs laboratory tests, but distributes much needed blood products to our patients. I feel rewarded each and every day that I can help save a life through my efforts. Blood donation is essential to our job and relies on the volunteer donation of others. I have spent the last 14 years of my life studying and working in a very busy Blood Bank and have learned so much as a Specialist in Blood Banking.