Frequently Asked Questions

Q: Should I refrigerate the sample?
No, do not refrigerate any samples.

Q: How can I access patient results directly from Care Web?
HLA typing reports are available under the recipient on CareWeb. Please be advised these are secure orders and an audit trail is maintained on all persons viewing these reports. Antibody screening results will be available on CareWeb in the very near future.

Q: When should a post-transfusion sample be collected to monitor HLA antibodies?
A sample should be drawn approximately 14 days post-transfusion.

Q: What should I do if a patient leaves the clinic without getting their blood drawn for Histocompatibility?
Notify the Histocompatibility Lab and we can send the patient a kit to have the samples drawn.

Q: How long does it take to get HLA typing results?
Molecular testing is performed to identify HLA class I and class II antigens. The turn around time is ten working days.

Q: What is HLA Typing?
HLA antigens are glycoproteins, the product of multiple, closely linked genes on a single chromosome usually inherited as an intact unit. HLA class I typing refers to the HLA-A, B, and C loci. HLA class II typing refers to the HLA-DRB1,3,4,5 and DQB1 regions. The laboratory utilizes molecular methods for defining HLA class I and class II antigens and performs HLA typing on approximately 5100 subjects per year.

Q: What is a Crossmatch?
Crossmatch analysis detects the presence of donor-reactive alloantibodies. The method used is CDC (complement dependent cytotoxicity). The crossmatch may be performed using unseparated T and B donor lymphocytes, or isolated donor T cells (detecting class I antibody), or isolated donor B cells (detecting class II antibody). Positive crossmatch results are graded from weak positive to strong positive.

Q: What is Antibody Screening?
Antibody screening identifies HLA class I and class II antibodies. The antibody screening methodologies include CDC (complement dependent cytotoxicity) and ELISA (Enzyme Linked Immunosorbent Assay) assays. Each method has advantages and is utilized in different cases. The PRA (panel reactive antibody) is calculated and antibody specificity is determined by analyzing the antibody screening data.