Hemolytic Uremic Syndrome Dense Deposit (Renal Genetic Test)
Label Mnemonic: HUSDD
Epic Lab Code: LAB7435
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Whole Blood
Collection Medium:
Red top tube 5 mL (Clot Activator)
Minimum:
Preferred Minimum: 1 mL serum
Absolute Minimum: 0.5 mL serum
Turn Around Time:
1 month
Reference Range:
Normal (<3%); 1+ (3%-20%); 2+ (20%-40%); 3+ (40%-60%); 4+ (60%-80%);
5+ (80%-100%, complete hemolysis)
Interpretive Data:
Hemolytic Assays of Complement Activity
The Clinical Diagnostics Service of the Molecular Otolaryngology Research Laboratory is a Joint Commission-approved CLIA-accredited diagnostic laboratory.

Sheep Erythrocyte Lysis Assay
Sheep erythrocytes are non-activating surfaces. This assay measures complement-mediated lysis of sheep erythrocytes secondary to activation of the alternative pathway (AP). Lysis can be seen in the serum of patients with aHUS and DDD.

Sensitivity Unknown
Comments:
Please print, complete and submit the Kidney Testing Requisition Form from the Molecular Otolaryngology & Renal Research Laboratory, to Specimen Control/Mailouts with the specimen and the Epic Requisition.
Methodology:
Sheep erythrocytes are used as index cells in this assay. Sheep erythrocytes generally act as non-activators of complement-mediated lysis in human serum. A small number of C3b molecules spontaneously generated through AP tick-over are deposited on the surface of sheep erythrocytes. In normal human serum, factor H binds to C3b molecules through its N-terminal domains and to sheep erythrocytes through its C- terminal domains. These interactions result in efficient protection of sheep erythrocytes against complement and no lysis is observed (Dragon- Durey et al, 2005, Józsi et al, 2007).

Abnormal hemolytic activity may be seen when serum from patients with aHUS is used in this assay if these patients carry either genetic mutations or acquired risk factors for aHUS such as FH autoantibodies. While abnormal hemolytic activity may also be seen with serum from patients with DDD if these patients carry either genetic mutations or acquired factors for DDD such as C3 nephritic factors, hemolysis will be absent when consumption of AP proteins has been extensive and only a small amount of AP proteins remain in the serum.
CPT Code:
86161