Blood Preservation and Blood Products

Flashcards covering blood preservation methods, anticoagulants inclusive of proper concentrations, storage protocols for blood products, hematological reference values, and diagnostic tests for hemoglobinopathies as per the HEM 102 lecture by Prof M. A. Durosinmi.

EDTA (Sequestrene)

A calcium chelator that renders Calcium non-ionizable; used at a concentration of $1.5 \pm 0.25\,mg/ml$ of Whole Blood, it is the anticoagulant of choice for routine haematology work like blood counts and ESR.

Trisodium Citrate solution 109mmol/L

A calcium chelator used at $31.3\,g/L$ ($Na_3C_6H_5O_7.2H_2O$) that is the anticoagulant of choice for coagulation studies, Westergren ESR determination, and blood transfusion practice.

Heparin

An anticoagulant that inactivates thrombin (anti-thrombin) used at $15-20\,IU$ per ml of blood; it is the choice for osmotic fragility and biochemistry tests but limits donor blood shelf life to $24$ hours.

Oxalate-fluoride

An anticoagulant where oxalate chelates calcium and fluoride inhibits the enolase enzyme to prevent glycolysis; it is the choice for determining glucose and lactate levels.

70% alcohol (ethanol)

A fixative used to maintain the structure of cells in peripheral blood, bone marrow on slides, and aspirated or biopsied tumour cells.

CPD-A (Citrate Phosphate Dextrose Adenine)

The anticoagulant used to preserve Red cells and whole blood at $1-6^\circ C$ for up to $42$ days.

Glycerol

The preservative used for frozen Red cells stored at $-60$ to $-80^\circ C$ for up to $10-14$ years.

Platelets Storage

Stored at Room temperature with rotation for a duration of $5$ days.

Fresh Frozen Plasma (FFP)

Plasma frozen at $-25^\circ C$ or below for up to $12$ months; it contains all coagulation factors including labile factors $V$ and $VIII$, fibrinogen, and fibronectin.

Cryoprecipitate

A blood product frozen at $-18^\circ C$ for $12$ months containing fibrinogen, factor $VIII$, vWF, fibronectin, and $FXIII$; a unit is $15-20\,mL$.

Mean Corpuscular Volume (MCV)

A red cell index with a normal value of $85 \pm 8\,fl$ ($1fl = 10^{-15}l$).

Mean Corpuscular Haemoglobin (MCH)

A red cell index with a normal value of $29.5 \pm 2.5\,pg$ ($1pg = 10^{-12}g$).

Mean Corpuscular Haemoglobin Concentration (MCHC)

A red cell index with a normal value of $33 \pm 2\,g/dl$.

HbSS

Also known as Sickle cell anaemia (SCA); it has a prevalence of $2-3\%$ in Nigeria.

Sickle Cell Trait (HbAS)

A haemoglobin variant with a prevalence of $26\%$ in Nigeria.

Thalassaemia

A disorder characterized by the absence or reduction in the synthesis of polypeptide chains, where $\alpha$-chain deficiency leads to $\alpha$-thal and $\beta$-chain deficiency leads to $\beta$-thal.

Hb Bart's

A tetramer of gamma chains ($\gamma_4$) associated with $\alpha^o$-thal ($--/--$) which is incompatible with life.

Solubility Test

A diagnostic test using sodium dithionite; insoluble $HbS$ forms a cloudy mixture, while soluble deoxygenated haemoglobins ($A$, $F$, $E$, $C$, $D$, $O$) form clear solutions.

Isoelectric focusing (IEF)

A specialized electrophoretic technique for newborn screening run at pH between $3$ and $10$ in polyacrylamide gel.

DNA analysis

The only confirmatory test for the Sickle gene.

Blood Group Antigens

Carbohydrate or proteins found on the surfaces of blood cells (red cells, white cells, platelets), body tissues, fluids, bacteria, and viruses.

Group AB Individual

An individual whose red cells contain both $A$ and $B$ antigens and whose serum lacks both anti-$A$ and anti-$B$ antibodies.

Rh-D- Frequency

In South West Nigeria, this blood group system frequency is $4\%$, while $Rh-D+$ is $96\%$.