ASCP SBB flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Immune anti-A,B

Group O serum contains anti-A, anti-B and anti-A,B, an IgG antibody reacting with both A and B cells; it is why group O plasma is not universally compatible for plasma transfusion.

D antigen immunogenicity

D is the most immunogenic red cell antigen; up to 80% of D-negative recipients exposed to D-positive red cells form anti-D, which is why RhIG prophylaxis is used.

Check cells

IgG-sensitized human red cells added to a negative AHG tube; agglutination proves antihuman globulin was present and active, validating the negative result.

Dosage effect

Antibodies to Rh, Kell, Duffy, Kidd and MNS antigens react more weakly with heterozygous cells expressing a single dose, so homozygous cells are chosen for identification panels.

Kidd antibody evanescence

Anti-Jka and anti-Jkb fall below detectable levels within weeks to months of stimulation, so re-exposure can produce an anamnestic delayed hemolytic transfusion reaction.

Whole blood donation interval

Donors must wait 56 days between whole blood donations, weigh at least 50 kg, and have hemoglobin of 12.5 g/dL if female or 13.0 g/dL if male.

Platelet storage conditions

Platelets are held at 20-24°C with continuous agitation for up to 5 days, or 7 days with approved pathogen reduction, and are never refrigerated because cold impairs function.

Leukoreduction threshold

Leukoreduced components contain fewer than 5 x 10^6 residual white cells per unit, reducing febrile nonhemolytic reactions, HLA alloimmunization and transfusion-transmitted CMV.

FFP freezing window

Fresh frozen plasma is frozen within 8 hours of collection, or within 24 hours for FP24, then stored at -18°C or colder for up to 12 months.

Irradiation dose

Cellular blood components are irradiated with 25 Gy (2500 cGy) to 50 Gy at the container center to inactivate donor T lymphocytes and prevent transfusion-associated graft-versus-host disease.

Cryoprecipitate contents

Cryoprecipitate is the cold-insoluble fraction of thawed plasma and is rich in fibrinogen, factor VIII, von Willebrand factor, factor XIII and fibronectin.

Restrictive transfusion threshold

Most stable adult inpatients receive red cells at a hemoglobin of 7 g/dL; 8 g/dL applies to cardiac surgery and stable cardiovascular disease.

Platelet count triggers

Prophylactic platelets at 10 x 10^9/L, 20 x 10^9/L before central line or lumbar puncture, 50 x 10^9/L for major surgery, and 100 x 10^9/L for CNS or ocular surgery.

TACO versus TRALI

Both cause dyspnea and bilateral infiltrates within 6 hours, but TACO shows hypertension and elevated BNP from volume overload, whereas TRALI is noncardiogenic with fever.

Acute hemolytic reaction

Usually caused by ABO-incompatible red cells from a clerical or identification error; presents with fever, chills, flank pain, hemoglobinuria, hypotension and disseminated intravascular coagulation.

Massive transfusion definition

Replacement of one blood volume, or 10 or more units of red cells within 24 hours, managed with balanced 1:1:1 red cell, plasma and platelet ratios.

Westgard 1-3s rule

A single control value more than 3 standard deviations from the mean rejects the analytical run, indicating either random or systematic error.

Daily antisera QC

Anti-A, anti-B and anti-D are tested each day of use with known positive and negative red cells to confirm reactivity and specificity before patient testing begins.

Corrective and preventive action

A CAPA record documents the root cause investigation, the corrective step taken for a known nonconformity, the preventive step against recurrence, and verification that the fix worked.

Proficiency testing requirement

CLIA requires laboratories to enroll in an approved proficiency testing program, test unknown specimens, score satisfactorily, and investigate every unacceptable result.

Fatality reporting to FDA

A donation- or transfusion-related fatality must be reported to FDA CBER as soon as possible and no later than 7 days after the initial report.

ISBT 128 donation number

A globally unique, barcoded donation identifier with a check character that ensures traceability of each unit from collection through component processing to transfusion.

OSHA bloodborne pathogens standard

29 CFR 1910.1030 requires an exposure control plan, hepatitis B vaccination offered to at-risk employees, safer engineering controls, and post-exposure medical evaluation.

Look-back investigation

When a repeat donor later tests positive for HIV, HCV or HBV, prior recipients are traced and their physicians notified, covering donations from the preceding 12 months.

Minipool versus ID-NAT

Donor nucleic acid testing uses pools of 6 to 16 samples or individual donations; individual donation testing further shortens the window period at higher cost.

RHD genotyping indication

Molecular RHD testing resolves weak or discrepant D serology and separates weak D types 1 to 3, managed as D-positive, from partial D variants that can form anti-D.

Cell-free fetal DNA typing

Fetal RHD genotype is determined from cell-free DNA in maternal plasma, guiding whether anti-D immune globulin is needed during a D-negative pregnancy.

Chimerism testing

Short tandem repeat PCR quantifies donor and recipient DNA proportions after hematopoietic stem cell transplant to detect engraftment, mixed chimerism or early relapse.

CD34 engraftment dose

A minimum of 2 x 10^6, and preferably 2-5 x 10^6, viable CD34-positive cells per kilogram recipient weight predicts reliable neutrophil and platelet engraftment.

DMSO cryopreservation

Hematopoietic cell products are frozen with 5-10% dimethyl sulfoxide using controlled-rate cooling near -1°C per minute, then stored at -150°C or colder.

Cytokine release syndrome

A CAR-T cell toxicity of fever, hypotension and hypoxia driven by cytokine release, graded clinically and treated with tocilizumab, with neurotoxicity scored separately as ICANS.

Major ABO-incompatible graft

When donor red cells are incompatible with recipient plasma, such as an A graft into an O recipient, the product is red cell depleted before infusion to prevent hemolysis.