Single Antigen Bead Class I (A B C Loci)

What is Single Antigen Bead (SAB) Class I test?

Single Antigen Bead (SAB) Class I is a highly sensitive, bead-based HLA antibody test that detects and pinpoints IgG antibodies against specific HLA Class I antigens (HLA-A, -B, -C) in serum, reporting signal strength as mean fluorescence intensity to indicate antibody presence and relative strength. By using beads coated with single recombinant Class I HLA molecules, it provides allele-level specificity, enabling precise identification of donor-specific antibodies (DSA) and overall sensitization status for transplant decision-making.

Why consider Single Antigen Bead (SAB) Class I test?

• Assess pre-transplant HLA sensitization, perform a “virtual crossmatch,” and guide donor selection and immunosuppression to reduce antibody-mediated rejection risk.
• Detect and monitor Class I DSA before or after transplant, including low-level antibodies that screening assays may miss, improving risk stratification and outcomes.
• Resolve complex antibody profiles in highly sensitized patients where fine specificity affects compatibility and rejection risk.

Who should get this Single Antigen Bead (SAB) Class I test?

• Solid-organ transplant candidates and recipients (kidney, liver, heart, lung) for pre- and post-transplant antibody assessment, especially with prior transplants, transfusions, or pregnancies that increase sensitization.
• Patients with suspected or documented DSA, or with unexplained graft dysfunction where antibody-mediated mechanisms are a concern.
• Individuals requiring precise Class I antibody mapping when screening/panel-reactive tests are positive or inconclusive.

More Information about Single Antigen Bead (SAB) Class I test

Other names: SAB, Single Antigen Bead, Solid Organ Transplant, Kidney Transplant

A kidney transplant is surgery to place a healthy kidney from a donor into someone whose kidneys have failed. One working kidney can do the job of two, so only a single donor kidney is transplanted. Kidney transplantation involves assessing the recipient's overall health, ensuring a suitable donor match, and monitoring for complications post-transplant. This includes evaluating kidney function, matching tissue types (HLA typing), and assessing for antibodies that could cause rejection.