Blood Groups

Introduction to Blood Groups

• Discovery: Blood groups identified by Lansteiner.

Genetic Basis:

• Mnemonic: Chromosomes 19, 9, 1.

Antigen Presence on Red Blood Cells (RBCs):

• Based on antigens & oligosaccharides in RBC.

• Antigens: Agglutinogens.

• Antibodies: Agglutinins.

Landsteiner's Law

• Principle:
• If an antigen is present in RBC
• its corresponding antibody must be absent from serum.

• Exception:
• Rh antigen if absent in blood does not form Rh antibodies

• A antigen = N-acetyl galactosamine + H substance

• B antigen = Galactose + H substance

• H substance = Fucose + Glycolipid / Glycoprotein

• Associated Sugars:
• N-acetyl galactosamine (NAG)
• Galactose (GAL)
• Mnemonic: A Nag (hey nagame)→ B a Girl (oru girl avu)

Blood Group Antigen Sites

• ABO antigens are not confined to RBCs — also in body fluids of secretors, bacteria, and certain foods.
• RBC
• Saliva
• Amniotic fluid
• Semen
• Intestinal bacteria
• Food

Other Blood Group Systems

Bombay Blood Group:

• H antigen is missing.

• Results in: All antigens absent, all antibodies present (including anti-H).

• Associated with leukocyte adhesion defect type 2.

Types of LAD:

LAD1

• In LFA-1 integrin (CD 18, CD 11 defective) protein defect on phagocytes
• Leads to impaired migration and
• chemotaxis by C5a, IL-8, leukotriene B4 (LIC)

LAD Type	Defect	Clinical Features / Associations
LAD 1	Beta 2 integrin	Delayed umbilical cord shedding, Recurrent infections NO PUS dysfunctional neutrophils
LAD 2	Sialyl Lewis X (S-LeX) (selectin)	Bombay blood group (no H, A, B antigens; anti-H, anti-A, anti-B Abs) + Delayed umbilical cord shedding Bombay blood group = “Oh”
LAD 3	Kindlin-3 (FERMT3 gene)	Bleeding manifestations

• Mnemonic:
• Bombayil (Bombay blood group) kond povan 2 (LAD 2) pere selct (Selectin) cheyth → SaLu (Sialyl Lewis)
• But Salu nte umbilical cord shed ayilla → kond povan patiilann paranju
• Salu ne kude integrate (Integrin) cheyyan umbilical cord valichu uuri (↓ umbilical cord shedding)
• Apo bleed cheyth → 3 (LAD 3) kinder (Kindlin) joyum ferraro roshe (FERMT 3) yum vangi koduth

Universal Donors and Plasma Donors

• Universal Donor (for Red Blood Cells):
• O blood group: Lacks A and B antigens, preventing antigen introduction.

• Universal Plasma Donor (for Plasma):
• AB blood group: Lacks anti-A and anti-B antibodies, preventing antibody introduction.

Blood Grouping Methods

• Basic Principle:
• Mix blood with anti-sera (chemicals with antibodies) → observe for clotting (agglutination).

• Anti-Sera Color Coding:
• Mnemonic: BYG

Anti-Sera Color Coding	Antibody	ㅤ
Blue	Anti-A	ㅤ
Yellow	Anti-B	ㅤ
Gray	Anti-D	For Rh positive/negative

• Anti-Human Globulin (AHG):
• Green color;
• used in Coombs test.

• Methods:
1. Slide Method.
2. Test Tube Method.
3. Eliza Plate:
• 96 wells (8x12).
• Tests approx. 90 patients at once.
4. Gel Card:
• Maintains blue, yellow, gray color coding.
• Interpretation:
• Line at top → reaction positive.
• Line at bottom → reaction negative.
5. Automated Machines.

Rh System

Antigens

• C, D, E

Types

• Based on presence of D antigen:
• Rh+: D antigen present
• Rh- : D antigen absent

Clinical Significance

• Rx: Anti Rh antibodies.

Blood Donation Process and Equipment

• Biomixer: Machine for blood collection.
• Mixer: Rocks to mix blood with anticoagulant.
• Autoclamp: Auto-stops collection at desired volume (e.g., 350 ml).
• Display: Shows collected blood volume.

Blood Donation Criteria

• Age: 
• > 18 years & < 65 years

• Hemoglobin: > 12.5 g/dL.

• Weight: > 45 kg.
• 45-55 kg: 
• 350 ml blood collected.
• Above 55 kg: 
• 450 ml blood collected.
• Blood banks use both 350 ml and 450 ml bags.

Types of Blood Bags

• TAT Bag (Top and Top):
• Mother bag (initial whole blood collection).
• All tubings on top.
• Whole blood → separated into packed RBCs, platelet-rich plasma, fresh frozen plasma.

• TAB Bag (Top and Bottom):
• Mother bag with some tubings on top, some at bottom.

• PDB Pouch (Pre-Donation Bag):
• Small pouch collects initial 10-30 ml blood.
• Purpose: Prevents skin contamination (bacteria, viruses) from entering main bag.

Leukoreduction Filter:

• Removes White Blood Cells (WBCs).

• Reasons for WBC removal:
• Prevent CMV transmission 
• Most common transfusion related infection
• Prevent Febrile Non-Hemolytic Transfusion Reaction
• Most common transfusion reaction.
• Causes fever due to interleukins from WBCs.

Penta Bag:

• Mnemonic: PE for penta, PE for pediatric blood transfusion.

• For pediatric transfusions.

• Large donation (e.g., 450 ml) → divided into four smaller pouches (100-120 ml each).

• Prevents wastage

Screening for Transfusion Transmitted Infections (TTI)

• Primary Prevention → PROSPECTIVE SCREENING

• Mandatory screening in India for:
• HIV (1 and 2).
• Hepatitis B Virus
• Hepatitis C Virus
• Malaria.
• Syphilis.

Indications for Irradiated Blood Products

• Immunocompromised recipients

• Recipients getting blood from close relatives

• Used to prevent GVHD in susceptible recipients

Anticoagulants and Shelf Life of Blood Components

 

• Order of Usage when all three available:
• FFP > RBC > Platelet

• General Rule:
• Power failure/machine malfunction
• shelf life of components reduces to 1 day.
• Transfusion should be completed within 4 hours
• (of receiving the blood from the blood bank)

Apheresis Machine

• Advanced machine:
• Separates blood components from donor in real-time
• Without donor leaving.

• Process:
• Two cannulas inserted
• Machine separates RBCs, platelets, FFP.
• Desired component kept (e.g., platelets for dengue)
• Unused components returned to donor immediately.

• Examples: Platelet apheresis, Plasma apheresis.

Improved Neubauer Chamber (Hemocytometer)

Pipettes for Cell Counting:

Diluting Fluids:

• Piolet’s Fluid
• Eosinophils

Sahli's Hemoglobinometer

• Used for Hemoglobin estimation.

• Principle:
• Converts hemoglobin → acid hematin (brown color)
• using N/10 HCl
• Dilute with distilled water until color matches comparator
• Read Hb level

Measurement of PCV and ESR:

ㅤ	Wintrobe tube	Westergren pipet	Automated ESR
Tube	Small	Long	ㅤ
Measures	PCV and ESR	Only ESR	ㅤ
ㅤ	Rob both PCV and ESR	WEST → ESR → Only ESR	ㅤ
Vacuntainer	Lavender	Light blue	Black
ㅤ	Lovely Wind	Western blue	Black Auto

• Light Blue
• ESR → 4:1
• APTT/PT/INR → 9:1

Massive Blood Transfusion

• Defined as transfusion of:
• ≥ 50% of total blood volume within 4 hours
• Replacement of entire circulating volume in 24 hours.
• >10 units / 24 hours
• >4 units / 1 hour

Complications (CATCH Mnemonic):

• Met acidosis → Metabolic alkalosis (D/t citrate toxicity).
• Citrate gets metabolized to bicarbonate → raises pH

• Temperature (Hypothermia):
• Due to cold blood.

• Citrate toxicity:
• Due to CPDA anticoagulant.
• Citrate bind to Calcium and Magnesium
• Causes Hypocalcemia (symptoms: tingling, numbness).
• Causes Hypomagnesemia
• Citrate Load & Tolerance
• Each unit of blood contains ~3 g citrate
• Healthy liver metabolizes 3 g citrate in ~5 minutes
• If transfusion exceeds 1 unit/5 min
  → serum Ca++ and Mg++ drop due to citrate binding

• Hyper K+ >> Hypo K+ 
• Initially Hypokalemia
• Hyperkalemia:
• ↓ ATP in stored blood → Failure of Na K ATPase pump → RBC lysis in stored blood → ↑ release of Potassium
• can cause arrhythmias.

• TRALI vs TACO

• Lactic acidosis

Key Electrolyte & Acid-Base Complications

Do Not Confuse With – Refeeding Syndrome

Fresh Frozen Plasma

Indications

• Replacement of isolated factor deficiency.

• Platelet count <50 x10^9/L.

• Reversal of warfarin effect.

• Clotting disorder (e.g., due to liver disease).

• Prolonged INR.

• Massive blood transfusion (>1/2 blood volume within several hours).

• Treatment of TTP.

Very Important

• Patient with liver disease + Hematemesis + high INR → Give FFP.

Tumor Lysis Syndrome (TLS)

• Hematological emergency

• Occurs after chemotherapy, radiotherapy, or surgery

• Common in:
• Acute Lymphoblastic Leukemia (ALL)
• Burkitt’s Lymphoma

• Due to rapid lysis of tumor cells

ALKALANISATION IS NOT TO BE DONE for Uric acid crystals in TLS

• because 2 stones are formed
• Phosphate stone → ↑↑ In alkaline medium
• Alkalinisation → ↑ Phosphate stones
• Uric acid stone → ↑↑ in acidic medium

Pathophysiology

• Cell lysis releases:
• Uric acid (Urate)
• Potassium
• Phosphate

Electrolyte Changes

Diagnosis

• Based on Cairo-Bishop Criteria
• Includes both laboratory and clinical criteria

Complications

• Acute Renal Failure

• Cardiac arrhythmias

• Neurological symptoms

Management

Supportive Care

• IV Fluids (IVF) for hydration

• Avoid urinary alkalinization

Prevention

• Allopurinol
• ⛔ xanthine oxidase
• Reduces uric acid production

• Aggressive hydration
• Maintains high urine flow

• Febuxostat
• Selective xanthine oxidase inhibitor
• Alternative to allopurinol

Treatment for Severe TLS / Renal Failure

• Rasburicase
• Recombinant urate oxidase
• Converts Uric acid → Allantoin (soluble)

• Renal replacement therapy may be required