ASCP Specialist in Blood Banking (SBB) practice test

A prenatal patient is found to have anti-D with a titer that has risen significantly over two consecutive measurements. To assess the fetus for anemia noninvasively, which test has largely replaced amniocentesis for monitoring?

A patient develops fever, hypotension, hemoglobinuria, and back pain shortly after starting a red cell transfusion. The transfusion is stopped immediately. Which type of transfusion reaction is most consistent with this acute presentation?

A panel result shows the patient serum reacting with all panel cells and the autocontrol. The reactions are equal in strength across all cells and occur at the antiglobulin phase. The patient has a positive DAT with IgG. Which finding best explains this picture?

A weak D test is performed on a donor unit that typed as Rh negative at immediate spin. The unit reacts positively at the antiglobulin phase of the weak D test. How should this unit be labeled?

A patient with IgA deficiency and a history of anaphylactic transfusion reactions requires red cells. Which product modification is most appropriate to prevent another anaphylactic reaction?

During antibody identification, a technician suspects two antibodies are present. To help separate them, panel cells with homozygous antigen expression are selected. Selecting homozygous cells is most useful for detecting antibodies that show which characteristic?

A specimen for the antibody screen is collected and a positive screen is detected. The reagent screening cells are group O. Why are group O cells used for antibody screening rather than group A or B cells?

A massively transfused trauma patient has received many units of red cells stored for an extended time. Which electrolyte abnormality is most associated with rapid transfusion of large volumes of stored red cells?

A patient serum reacts with panel cells at room temperature but the reactions disappear when the test is performed strictly at 37 degrees Celsius and the antiglobulin phase. The antibody reacts with adult cells but not cord cells. Which antibody is most consistent with this behavior?

An eluate is prepared from red cells with a positive direct antiglobulin test. The eluate is used primarily to accomplish which goal?

A patient develops sudden respiratory distress and pulmonary edema within six hours of transfusion, with no evidence of circulatory overload. Donor plasma is found to contain HLA antibodies. Which transfusion reaction is most consistent with this presentation?

A patient serum reacts with all panel cells, but treating the serum with a thiol reagent such as dithiothreitol abolishes the reactivity. The DAT is negative. Which antibody class is most likely responsible?

A mixed-field agglutination pattern is observed when testing a patient red cells with anti-A. The patient was recently transfused. Which explanation best accounts for this mixed-field reaction?

A platelet product must be irradiated before transfusion to a severely immunocompromised stem cell transplant patient. What complication does irradiation of cellular blood products prevent?

A panel shows the patient serum reacting at the antiglobulin phase, and ficin-treated panel cells show enhanced reactions for some specificities while others are destroyed. An antibody whose corresponding antigen is destroyed by ficin would include which of the following?

A patient typed as group A but the reverse type shows weak or missing anti-B. Which factor is the most common cause of weak or absent expected ABO antibodies in the reverse grouping?

An obstetric patient who is Rh negative delivers an Rh positive infant. A Kleihauer-Betke or flow cytometry test is performed after delivery. What is the purpose of this fetal red cell quantitation test?

A patient has an antibody to a high-frequency antigen, and compatible units are extremely difficult to find. Which strategy is most appropriate to locate compatible blood?

A delayed hemolytic transfusion reaction is suspected several days after a transfusion. Laboratory findings include a falling hemoglobin, a newly positive DAT, and a previously negative antibody screen now showing an alloantibody. What is the most likely mechanism?