Antihuman Information and Courses from MediaLab, Inc.

The auto control and all panel cells are showing reactivity at the AHG phase, which indicates a possible autoantibody (warm).IS = Immediate Spin; AHG = Antihuman Globulin Phase; CC = Check Cells; AC = Auto Control; ND= Not done

The antibody screen can provide sufficient data to make initial hypotheses regarding the likely antibody specificities and may be useful to presumptively rule-out some antibody specificities. When analyzing the antibody screen data, the strength/characteristics of reactions (for example, mixed-field or weak versus strong), the phase of testing (for example, room temperature versus AHG), and the pattern of reactivity (which cells react and which do not) are all important factors that will provide clues about the possible identification of the antibody(ies). Many antibodies exhibit dosage, that is, they react more strongly with homozygous cells than with heterozygous cells. If a tube method is used, reactions are usually read at immediate spin and AHG phase. If a gel method is used, reaction readings are done only at AHG phase. Reactions occurring only at immediate spin phase could indicate a possible IgM antibody, cold agglutinin, or rouleaux. Reactions occurring in the AHG phase could indicate a possible IgG antibody. Reactions occurring in both reaction phases could indicate a combination of both IgM and IgG antibodies or a strong IgM antibody that carries through to AHG phase. The presence of multiple antibodies should be considered if reactions vary in strength or there are two separate reaction patterns in the IS and AHG phases.

Antibodies have optimum temperatures for reactivity. Reaction readings can be made at different phases: after immediate spin, after incubation at 37°C, and after the addition of antihuman globulin (AHG) and centrifugation. Reactivity in a certain phase will help to determine whether the antibody is cold reacting (IgM) or warm reacting (IgG). It will also help to distinguish between antibodies that are clinically significant and not significant. Clinically significant antibodies that are capable of causing acute and delayed hemolytic transfusion reactions (HTR) or hemolytic disease of the newborn (HDN) are usually IgG and react best in the AHG phase.Readings can be done at all three phases if a tube method is used. If a gel method is used, readings are done only at AHG. Immediate spin: Antibodies reacting in this phase tend to be cold reactive. They are usually IgM class and not clinically significant (with the exception of the A and B antibodies). 37°: Antibodies that react in this phase include strong IgM or IgG antibodies. After incubation, the tubes are examined for the presence of hemolysis. If complement was bound during incubation then hemolysis could be seen. NOTE: This reaction would only occur in serum samples. If EDTA plasma samples are used for testing, the complement cascade has been halted. Magnesium and calcium ions are not available for complement to be activated. AHG:Antibodies reacting in this phase are considered clinically significant. They are usually warm reactive and IgG.

Based on the results of the mini-panel, the laboratory concluded that only anti-D was present and that it was consistent with administration of RhIg at 28 weeks.Patient A.D. delivered a 5 lb 13 oz female by C. section with serologic test results on cord blood as follows. Well washed cord red cells were used for ABO and Rh(D) typing to remove possible Wharton's jelly.Before proceeding to the next page, evaluate if the infant's ABO and Rh(D) types are valid. You will be asked questions that assess basic knowledge of blood grouping practices and test results for newborns. ABO Forward Group ABO Reverse Group Rh anti-A anti-B A1 cells B cells anti-D* 0 0 NT NT 3+ NT = not tested / * monoclonal IgM anti-D DAT Reagent DAT CC Polyspecific AHG w+ 2+ W+ = microscopic positiveAHG = antihuman globulin serum CC = IgG sensitized cells Note: It is the lab's policy to add IgG sensitized cells to weak antiglobulin test results.