| What is Coomb's test | Direct Coombs Test: This test detects antibodies (Abs) on the surface of red blood cells (RBCs).
It is utilized when suspecting hemolytic anemia due to various causes such as infection, autoimmune diseases, or reactions to medications.
Coombs reagent is added to detect Abs bound to RBCs. A positive result indicates hemolysis.
Indirect Coombs Test: This test identifies Abs in the patient’s serum. RBCs are mixed with patient serum, followed by the addition of secondary Abs. This is performed prior to transfusion to determine compatibility. It is crucial especially in cases where the patient may have Abs against the donor’s blood due to blood group difference |
| What is alloimmunization? | In cases such as when the mother is blood type O- and the fetus is O+, the mother may develop anti-Rh antibodies upon exposure during delivery.
To prevent this, "RhoGAM" is administered to suppress the mother’s immune response against Rh-positive blood cells.
This is typically administered during the second pregnancy between 32-36 weeks |
| What are hemolytic reactions? | Immunological vs. Non-immunological
Acute vs. Delayed
Hemolytic Reactions Hemolysis may occur due to compatibility errors in the lab, rare blood types, or during emergencies such as wartime. Clinically, signs may include fever, tachycardia, and hypotension resembling sepsis. |
| How is management of suspected hemolysis? | Discontinue transfusion immediately.
• Repeat Coombs test.
• Ensure ABC (Airway, Breathing, Circulation) assessment.
• Monitor for signs of fluid overload.
• Evaluate laboratory parameters including indirect Coombs, LDH, Bilirubin, and Haptoglobin levels |
| What are non-hemolytic reactions? | Rare occurrences may involve inflammatory responses,
potentially related to anti-HLA antibodies. However, modern leukoreduction techniques reduce the likelihood of such reactions. Symptoms may include chills, fever, and hypotension. |
| What are other complications and their managements in transfusion? | Allergic reactions and infectious diseases such as CMV,
hepatitis, HIV, and EBV may also occur, particularly in settings with inadequate blood product control.
Management of Infectious Complications In cases of suspected infection, discontinue transfusion, monitor vital signs, obtain blood cultures, and initiate appropriate antibiotic therapy |
| What is transfusion related acute lung injury (TRALI) | Transfusion-Related Acute Lung Injury (TRALI) typically presents within 6 hours of a transfusion, although it can manifest up to 24 hours post-transfusion
Symptoms of TRALI include acute respiratory distress, hypoxemia, fever, and hypotension.
TRALI is caused by an immune reaction involving donor antibodies directed against recipient leukocytes, leading to endothelial damage and increased pulmonary vascular permeability.
The recommended treatment for TRALI is supportive care, including oxygen therapy, mechanical ventilation, and hemodynamic support as needed |
| How is onset, symptoms and pathophysiology of transfusion associated GVHD? | Onset: TA-GVHD typically manifests within 1 to 6 weeks after transfusion, with symptoms becoming apparent around 7 to 14 days post-transfusion.
Symptoms: TA-GVHD presents with symptoms similar to classical GVHD, including skin rash, diarrhea, fever, liver dysfunction, and bone marrow suppression.
Pathophysiology: TA-GVHD occurs when viable T lymphocytes present in the transfused blood recognize the recipient's tissues as foreign and mount an immune response, leading to tissue damage. Unlike classical GVHD, which primarily occurs after allogeneic hematopoietic stem cell transplantation, TA-GVHD involves immunocompetent donor T cells attacking host tissues in immunocompromised recipients |
| What are risk factors for transfusion GVHD? | The risk of TA-GVHD is highest in recipients who are severely immunocompromised, such as those undergoing hematopoietic stem cell transplantation, receiving immunosuppressive therapy, or having congenital immunodeficiencies. Irradiation of blood products can mitigate this risk by inactivating donor T cells. |
| How is prevention of transfusion GVHD? | To prevent TA-GVHD, blood products intended for immunocompromised recipients are often irradiated to eliminate donor T cells' proliferative capacity while maintaining their hemostatic function.
Given the severity of TA-GVHD and its high mortality rate, prompt recognition, and supportive care are critical. Any suspicious cases should be reported promptly, and patients may require aggressive immunosuppressive therapy to manage the immunemediated damage |
| What are some prerequisits in blood transfusion? | Red Blood Cells (RBCs): Anucleated cells. Each hemoglobin (Hb) molecule comprises four heme groups, consisting of two alpha and two beta subunits. Conditions resulting from the loss of a heme group include thalassemia (minor vs. major).
Adult Bone Marrow: Located in the femur, sternum, and hip. Bone marrow aspiration is typically performed two finger-widths below the sternal notch or in the hip, yielding a fluid containing RBCs, white blood cells (WBCs), and platelets.
RBC Renewal: RBCs are replenished approximately every 120 days. Continuous RBC production without disruption leads to constitutive polycythemia or erythrocytosis.
HbA1c Testing: Conducted every three months, this test measures glucose levels attached to Hb, reflecting RBC turnover. |
| What is anemia? | Normal Hemoglobin Levels: >15 g/dL in males and >12 g/dL in females. Levels below these thresholds indicate anemia.
Management Approach: When encountering anemic patients, assess hemodynamic stability. In cases of hypotension and low oxygen saturation, evaluate the need for transfusion |
| What are anemia etiologies? | Anemia may stem from central (bone marrow-related) or
peripheral causes (hemolytic anemia, hemorrhage).
Diagnostic Considerations: Symptoms and clinical history help discern anemia types and underlying causes |
| How is blood component processing? | Leukoreduction is a process implemented in modern blood banking to reduce the number of white blood cells (WBCs) in blood products, including red blood cells (RBCs) and platelets.
The primary goal of leukoreduction is to decrease the risk of transfusion-related complications, such as febrile non-hemolytic reactions, alloimmunization, and transmission of infectious agents carried by white blood cells.
Leukoreduction also helps mitigate the inflammatory response associated with transfusion, particularly in immunocompromised or critically ill patient |
| What are special considerations in transfusion? | Patients undergoing hematopoietic stem cell transplantation (HSCT), particularly those with lymphoma or other hematologic malignancies, require special
considerations regarding transfusion therapy.
Irradiated blood products are recommended for these patients to prevent graft rejection and minimize the risk of transfusion-associated graft-versus-host disease (TA-GVHD). Irradiation effectively prevents the proliferation of donor T lymphocytes present in transfused blood products, reducing the likelihood of immune-mediated complications. |
| What is normal platelet count? | A normal platelet count typically ranges from 150,000 to 400,000 platelets per microliter (μL) of blood. Counts below this range are considered thrombocytopenia, indicating a decreased number of platelets in the bloodstream.
Thrombocytopenia can result from various causes, including decreased production, increased destruction, or sequestration of platelets. |
| How is clinical assessment of platelets? | Patients with low platelet counts should be evaluated for signs and symptoms of bleeding, such as petechiae, ecchymoses, hematomas, mucosal bleeding, and prolonged bleeding from wounds or invasive procedures.
The severity and frequency of bleeding symptoms guide the urgency of platelet transfusion and other interventions |
| What are BG considerations in transfusion? | Incompatible blood transfusions can lead to transfusion reactions, including hemolytic reactions, which may result in severe complications and even death.
Therefore, ensuring ABO and Rh compatibility is essential for safe transfusions |
| How is Coomb's testing of BG? | Coombs tests are laboratory tests used to detect the presence of antibodies or complement proteins bound to the surface of red blood cells (RBCs).
The direct Coombs test (direct antiglobulin test, DAT) detects antibodies or complement proteins attached to the patient's own RBCs in vivo.
The indirect Coombs test (indirect antiglobulin test, IAT) detects antibodies in the patient's serum that may react with donor RBCs ex vivo.
Coombs testing is particularly useful in diagnosing autoimmune hemolytic anemias and determining compatibility in blood transfusions |
| How is hemolytic anemia evaluation? | Hemolytic anemia is characterized by premature destruction of red blood cells (hemolysis), resulting in anemia and related clinical manifestations.
Laboratory findings suggestive of hemolytic anemia include a positive Coombs test (DAT), elevated lactate dehydrogenase (LDH) levels due to release from damaged RBCs, decreased haptoglobin levels due to its consumption in scavenging free hemoglobin, and elevated bilirubin levels due to increased breakdown of hemoglobin. |
| What are labile blood products? | are blood components that have a limited shelf life and require special storage conditions to maintain their efficacy and safety. Here are 10 essential points about
labile blood products:
Definition: Labile blood products refer to blood components that are perishable and susceptible to degradation over time, necessitating careful handling and storage to maintain their therapeutic effectiveness |
| What are types of labile blood products? | Common labile blood products include:
Packed red blood cells (PRBCs)
Platelet concentrates
Fresh frozen plasma (FFP)
Cryoprecipitate |
| What are indications for transfusion? | Labile blood products are transfused to patients to
restore or maintain adequate levels of blood components, such as red blood cells, platelets, clotting factors, and plasma proteins, in various clinical scenarios, including:
Acute blood loss (e.g., trauma, surgery) Hemorrhagic disorders (e.g., thrombocytopenia, coagulopathy)
Hypovolemia and shock |
| What are storage conditions for transfusion and shelf life? | Labile blood products must be stored under controlled
conditions to preserve their integrity and functionality. This typically involves refrigeration for PRBCs, platelets, and FFP, while cryoprecipitate may require freezing at ultra-low temperatures.
Shelf Life: The shelf life of labile blood products varies depending on the component:
PRBCs: Typically stored at 1-6°C and have a shelf life of approximately 42 days.
Platelets: Stored at room temperature with constant agitation and have a shelf life of 5-7 days.
FFP: Stored at -18°C or colder and can be stored for up to 1 year.
Cryoprecipitate: Stored at -18°C or colder and can be stored for up to 1 year. |
| What is thrombophilia workup? | workup involves a systematic approach to identify underlying causes of hypercoagulability. Here's an elaboration on the workup process.
Hx (detailed, risk factors [thrombotic events, fam hx, meds, underlying medical conditions])
PE (venous and arterial thrombosis signs, inflammation of limb)
Labs (basic coagulation studies (aPTT, PT, TT), specific thrombophilia tests (protein C, protein S, antithrombin III, factor V leiden mutation, prothrombin gene mutation, APP antibodies), CBC, D-dimer (elevated - non specific))
Imaging (venous US (DVT), CT angio (visualization of arterial thrombosis), MRV (pelvis and abdomen thrombosis)
Special considerations (additional monitoring in pregnant women, vary based on age as well)
Genetic counseling (to understand themselves and fam) |
| How is hemophilia followup? | Regular monitoring may be necessary for patients with thrombophilia to assess the effectiveness of treatment and manage associated complications.
By following this comprehensive thrombophilia workup, clinicians can accurately diagnose hypercoagulable states and tailor management strategies to individual patient needs |
| What is primary hemostasis? | Platelet Adhesion: Injury to blood vessels exposes subendothelial collagen, triggering platelet adhesion. Von Willebrand factor (vWF) plays a crucial role in mediating the adhesion of platelets to exposed collagen.
Platelet Activation: Adhered platelets become activated, leading to changes in their shape and release of granule contents, including adenosine diphosphate (ADP) and thromboxane A2 (TXA2).
Platelet Aggregation: Activated platelets recruit additional platelets to the site of injury through the binding of fibrinogen to glycoprotein IIb/IIIa receptors, resulting in platelet aggregation and formation of a platelet plug |
| What are causes of secondary hemostasis? | By coagulation cascade intrinsic and extrinsic cascade.
Intrinsic Pathway: Initiated by contact between blood and exposed collagen, the intrinsic pathway involves factors XII, XI, IX, and VIII.
Extrinsic Pathway: Triggered by tissue factor (TF) released from damaged endothelial cells, the extrinsic pathway involves factors VII and tissue factor.
Common Pathway: Both intrinsic and extrinsic pathways converge on the common pathway, where factor X is activated to factor Xa. Factor Xa, along with factor Va and calcium ions, forms the prothrombinase complex, which converts prothrombin to thrombin |
| How is thrombin generation and regulation of coagulation? | Thrombin Generation: Thrombin plays a central role in the coagulation cascade by converting soluble fibrinogen into insoluble fibrin strands, which cross-link to form a stable fibrin clot.
Regulation of Coagulation: Coagulation is tightly regulated by anticoagulant factors such as antithrombin, protein C, and protein S, which inhibit the activity of thrombin and factors Va and VIIIa, thus preventing excessive clot formation |
| What are indications for transfusion of platelets in adults? | . |
