Blood Bank Review (Pink top)
Blood Group Antigens
Blood group is determined by antigens and antibodies in the blood. Blood group antigens are sugars attached to the surface of red blood cell.
ABO ANTIBODIES
Antibodies are blood proteins produced by the immune system in response to foreign substance in the body.
Blood group | Antigen(s) on RBCS | Antibodies present in the serum | Genotype(s) |
A
| A | Anti-B | AA OR AO |
B
| B | Anti-A | BB or BO |
AB
| A and B | None | AB |
0
| None | Anti-A and Anti-B | 00 |
Summary
Routine Blood bank tests
A pink tube is used for routine ABO, Rh and antibody screen test to ensure that compatible units are transfused. Incompatible blood can cause hemolytic transfusion reaction or death.
1. ABO, Rh typing is done to determine your blood type.
ABO grouping or typing can be performed in two ways;
a. Forward type: Anti A, Anti-B and Anti-D reagents are used in forward grouping to detect A, B, and D antigens present in the blood.
b. Reverse type: Reagent A1 and B cells are used in reverse grouping to detect specific ABO antibodies present in the blood.
2. Antibody screening detects presence of specific alloantibodies or autoantibodies to RBC antigens.
If an antibody is detected, extended crossmatch is performed to provide donor compatible blood. If no antibody is detected, an immediate crossmatch is performed.
3. Antibody identification is performed if the antibody screen result is positive.
4. Crossmatch is used to determine compatibility of donor’s RBCs with recipient’s blood.
a. Immediate spin crossmatch; If current or past antibody screening is negative
b. Full or extended crossmatch; if current or past antibody screen is positive
ABO Blood tying
ABO | ANTI A Forward typing | ANTI B Forward typing | ANTI D Forward typing | Rh Control Forward typing | A1 CELL Reverse typing | B CELL Reverse typing | BLOOD TYPE |
| 4+ | 0 | 4+ | 0 | 0 | 4+ | A POS |
| 4+ | 0 | 0 | 0 | 0 | 4+ | A NEG |
| 0 | 4+ | 4+ | 0 | 4+ | 0 | B POS |
| 0 | 4+ | 0 | 0 | 4+ | 0 | B NEG |
Universal recipient | 4+ | 4+ | 4+ | 0 | 0 | 0 | AB POS |
| 4+ | 4+ | 0 | 0 | 0 | 0 | AB NEG |
Universal donor | 0 | 0 | 4+ | 0 | 4+ | 4+ | O POS
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ABO blood group system is the only blood group system in which an individual have antibodies to antigens they lack without any prior exposure to red blood cell through transfusion or pregnancy.
For Blood Group A Positive; agglutination with anti-A, anti-D and B cells will be observed.
For Blood Group A Negative; agglutination with anti-A, and B cells will be observed. No agglutination with
anti D
For Blood Group AB Negative; agglutination with anti-A, and anti- B will be observed. No agglutination with anti D, A cells and B cells in reverse typing
For Blood Group O Negative; agglutination with A1 and B cells will be observed. No agglutination with anti A, B and D in forward typing.
Grading Reactions
Agglutination from 4+ to 1+; indicates presence of an antigen or antibody
Negative reaction means absence of an antigen or antibody
Rh Blood Group System
Of the five antigens only D testing is required. Rh test is used to identify Rhesus factor of blood. The term “Rh positive” indicates the presence of D antigen on red blood cells while Rh-negatives indicates the absence of D antigen on red blood cells.
If negative, individual is D negative
If positive, individual is D positive
Hematology Review (Lavender Tube)
MCV(fL) = Hematocrit (%) X 10 / RBC
Reference range; 80-100fL
MCH (pg) = Hgb X 100 / RBC count
Reference range: 26-34pg
MCHC (g/dL) = Hgb X 10 / Hematocrit (%)
Reference range: 32-37g/dL
Hgb= Hemoglobin
Causes of anemias (MCV)
Microcytic anemias can be due to Iron deficiency, thalassemia, anemia of chronic disease, sideroblastic anemia and lead poisoning
Macrocytic anemias can be due to Folate and Vitamin B12 deficiency
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MCV |
MCHC |
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<80fl (Microcytic anemia) |
<32g/dL (Hypochromic) |
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>100fl (Macrocytic anemia) |
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Coagulation Review (Blue Top)
Prothrombin time (PT) and activated partial thromboplastin Time (aPTT) tests are used to evaluate the ability to appropriately form blood clots.
A blue collection tube containing 3.2% sodium citrate anticoagulant is used for coagulation testing.
Routine Lab Tests
1. Activated Partial Thromboplastin Time (aPTT) is used to monitor patients on unfractionated heparin therapy.
2. Prothrombin Time (PT) is used to monitor warfarin or Coumadin therapy.
3. D-dimer; used to rule out blood clots
Urinalysis Review
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Urine Composition | Water and inorganic compounds. Urine organic substances: a. Urea (50%), creatinine and uric acid. b. Organic substances: vitamins, hormones, protein, and glucose. c. Urine inorganic substances: chloride, sodium, and potassium, magnesium, calcium, ammonium, sulfate, and phosphate. Chloride has the highest concentration followed by sodium and potassium.
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Color
| Yellow color of urine is derived from urochrome. |
Urine Volume | Dependent on body’s state of hydration; normal range of urine output 800-2000 mL/24 hr. |
Specific Gravity(S.G) | Normal random urine ranges from 1.003 to 1.030 Isosthenuric urine: 1.010 (fixed S.G ) |
pH of urine | 4.5 to 8.0 |
Creatinine clearance formula: | C (mL/min) = U X V X 1.73 m2 SA |
Cells High power field (hpf) Low power field (lpf) Confirmation test | 0-2 RBCs (hpf), 0-5 WBCs (hpf), 0-2 hyaline casts (Ipf) Acetest (Ketones), Icotest (Bilirubin), Sulfosalicylic acid precipitation (Protein) |
Clinical Chemistry Tumor Markers Review
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α 1 Fetoprotein (AFP) |
Increased level; Neural tube defects, spina bifida, and fetal distress Decreased levels associated with down syndrome
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Carcinoembryonic antigen (CEA) |
Colorectal cancer
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Human chorionic gonadotropin (Beta-hCG) |
Choriocarcinoma Ovarian tumors
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CA15-3 |
Detects breast cancer recurrence |
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CA125 |
Ovarian cancer |
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CA19-9
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Gallbladder, pancreatic, colorectal, and gastric carcinomas |
Microbiology Gram Positive Cocci Bacteria
Gram staining is a technique used to differentiate between two groups of bacteria based on their different cell wall constituents. Gram positive bacteria will stain violet due to the presence of a thick layer of peptidoglycan in their cell walls while gram negative bacteria stains red.