MORL Screening Methodology

Enzyme linked immunosorbent assay (ELISA)

  • 1ml frozen EDTA plasma

Click here to print sample and shipping requirements.

  • EDTA plasma samples must be frozen to below -80°C immediately after separation from cells and shipped on dry ice. These samples remain viable for at least six months when stored at -80°C.

  • All EDTA plasma samples MUST be processed and frozen down to -80°C immediately after collection
  • Labeled with the sample type AND patient’s name, DOB, MRN and sex
  • Cryovials should be put in zip lock bags and completely covered in dry ice to keep the sample frozen until it arrives in the lab
  • Shipped overnight on at least 5 lbs of dry ice
  • Shipping and receiving dock closed on weekends and holidays 
    • Deliveries accepted Monday - Friday 

If samples arrive thawed they will be REJECTED.

Click here to print sample and shipping requirements.

The activation of alternative pathway (AP) of complement generates the active proteolytic enzyme Bb. In the presence of C3b, factor B (MW: 93 kDa) binds to C3b to form the pre-convertase (C3bB). Factor D cleaves factor B releasing Ba (MW: 33 kDa) and generating the active proteolytic enzyme Bb (MW: 66kDa). The Bb subunit is catalytically active and cleaves new C3 to C3a and C3b. C3bBb recruits additional available C3b to form the C5 convertase, C3bBbC3b, launching terminal pathway activation. C3 convertase can be dissociated by spontaneous decay or complement regulators (factor H, CR1). It can also be inactivated by factor I-mediated C3b cleavage in presence of cofactors.

The common pathophysiological basis of both Dense Deposit Disease (DDD) and C3 Glomerulonephritis (C3GN) is dysregulation of the AP. Consumption of AP complement components is dependent on the degree of dysregulation of the C3 and C5 convertases. Plasma levels of Bb are elevated in both DDD and C3GN as compared to controls (p<0.001) consistent with dysregulation of the C3 convertase in both diseases (see Zhang et al. Defining the complement biomarker profile of C3 glomerulopathy, CJASN 2014).

Information

Quick Facts

  • CPT code: 86160 

  • Test code: 06BBL

  • Turnaround time: 2 weeks

  • Cost: $275

Requisition Form

To order:

Use this requisition form to order this test.

Background Knowledge

The activation of the alternative pathway (AP) of complement leads to the production of the active proteolytic enzyme Bb. When bound to C3b, factor B (MW: 93 kDa) forms the pre-convertase (C3bB). Factor D then cleaves factor B, releasing Ba (MW: 33 kDa) and generating the active proteolytic enzyme Bb (MW: 66 kDa). The Bb subunit demonstrates catalytic activity and cleaves new C3 into C3a and C3b. C3bBb recruits additional available C3b to form the C5 convertase, C3bBbC3b, which initiates terminal pathway activation. The C3 convertase undergoes dissociation through spontaneous decay and also secondary to complement regulators such as factor H and CR1. C3b can also be inactivated through factor I-mediated cleavage in the presence of cofactors. Bb levels more accurately reflect C3 convertase activity than do Ba levels. 

The Clinical Diagnostics Service of the Molecular Otolaryngology & Renal Research Laboratories is a CLIA-approved, Joint Commission-accredited diagnostic laboratory.