Adsorbing Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Adsorbing and links to relevant pages within the course.
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| Is It a Cold or a Warm Autoantibody? Cold antibody Immediate spin screen and panel cell reactions will be postive (W+ to 4+). The auto control may also be positive. AHG reactions may be weakly positive if the cold antibody is bound strongly to the red cells. Prewarming should prevent binding from occuring. So, prewarm panels and tests should have negative reactions.Warm antibody Immediate spin screen, panel cell and auto control usually not positive. AHG reactions will be positive including auto control (W+ to 4+). Prewarming of sample and reagents will not change positive reactions since they react best at 37°C and AHG phase. So, reactions will still be positive. Elution and autoadsorption techniques may be used to help further identify the antibody or to help identify other clinically significant antibodies that may be present.AutoadsorptionAutoadsorption is a technique that involves adsorbing unbound autoantibody from the patient's serum using the patient's own red cells. Once the autoantibody is removed, then testing can be performed to determine if any clinically significant antibodies are present. | View Page |
| What is an advanced technique that can help to determine the identity of other clinically significant antibodies that are present if a patient has a warm autoantibody? | View Page |
| Consulting the patient's physician If the physician had decided to continue transfusing the patient at this stage, the following information should be communicated: Although all donors appear to be compatible in the post-transfusion crossmatch, they are not. The results are false negatives - the patient's antibody has been "mopped up" by adsorbing to the incompatible transfused O Rh-negative RBC. Given that 6 donors were positive using the pretransfusion plasma, the antigen is a higher frequency antigen and most donors would likely be antigen-positive and incompatible. The patient's physician should consult the TS medical director before any decision to transfuse is made. Transfusing RBC before tests are complete requires physicians to sign an emergency release form in which they assume full responsibility. | View Page |
| Investigating weak antibodies In this case the patient's antibody has disappeared from the plasma by adsorbing to transfused donor red cells. It is detectable but unidentifiable in the post-transfusion red cell eluate. Several trial and error procedures exist to enhance weak antibodies. Which methods will enhance the reactivity of a given antibody depend on its characteristics. Methods to investigate weak antibodies include: Use a higher plasma to red cell ratio (add more antibody-containing plasma or eluate) Increase incubation time (if consistent with manufacturer instructions, if applicable) Use enzyme-treated panel red cells (enzymes enhance IgG antibodies in Rh and Kidd blood systems but denature some antigens, e.g., Fya, Fyb, S) Try alternative antibody detection methods, e.g., if using LISS routinely, try polyethylene glycol (PEG) or column agglutination methods such as gel, providing they have been validated for use in the TS laboratory. | View Page |