Reference no: EM132389301
There are two traditional clinical assays that measure the function of complement components by testing for the lysis of cells by patient serum.
In a CH50 assay patient blood is drawn and serum separated from it; serum has no cells but will have soluble proteins like complement. Patient serum is mixed with antibody-coated sheep red blood cells . The ability of the patient's serum to lyse the sheep red blood cells is then measured.
Note: In the CH50 assay sheep red blood cells are coated with antibody because this combination (cell + antibodies) can potentially trigger complement activation. The antibodies used in this assay would interact with complement components in the patient sera the same way the patient's own antibodies would
In the AH50 assay a similar test is performed but the blood cells used do not have antibody coating them. Basically the patient's serum is mixed with an animal's red blood cells (no antibodies present). The ability of the patient's serum to lyse the red blood cells is then measured.
In both the CH50 and the AH50 test lysis of the animal red blood cells indicate functional complement pathways (i.e., normal results).
Question:
If a patient has abnormal results in either the CH50 or AH50 test of complement function further testing of individual complement components can be done.
If you were treating a patient whose AH50 test came back abnormal (significantly lower level of cell lysis) but whose CH50 test was normal, would you order the following follow up tests? For each of the three tests answer whether you would order it and explain why or why not.
Test of the _______ level
Note: These tests would measure the level of the following in patient sera during either resting conditions (no immune response expected) and/or conditions that would normally lead to complement activation, whichever is appropriate. The results would then be compared to "normal" (non-deficient) levels