MORL Screening Methodology

C5 Convertase Stabilizing Assay with Properdin (C3CSAP) evaluates the capacity of C5Nefs to stabilize C5 convertase on sheep erythrocytes. 

  • 1ml frozen serum 

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  • Serum 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 serum 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.

 

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Dense Deposit Disease (DDD, aka Membranoproliferative Glomerulonephritis Type II, MPGNII)
C3 nephritic factors (C3Nefs), C5 nephritic factors (C5Nefs) and nephritic factor activity (nef activity) are defined as IgG autoantibodies to C3 convertase (C3bBb) that were first described by Spitzer and colleagues in 1969 as a substance in patient serum that constantly activated the alternative pathway cascade (Spitzer, 1969). They can be detected in ~80% of DDD patients and interfere with innate mechanisms that would otherwise control C3 convertase activity. Nephritic factors can also be detected in patients with partial lipodystrophy, meningococcal meningitis and post-streptococcal acute glomerulonephritis (Savage et al., 2009; Fremeaux-Bacchi, et al., 1994; Hulton, et al., 1992).

Information

Quick Facts

  • CPT codes: 86161
  • Test code: 06C5NEF
  • Turnaround time: 4 weeks
  • Cost: $250
Requisition Form

To order:

Use this requisition form to order this test.

Background Information

C5 nephritic factors (C5Nefs) are IgG autoantibodies that target the C5 convertase (C3bBbC3b). Formerly known as properdin-dependent C3Nefs, C5Nefs play a pivotal role in activating the C5 convertase as demonstrated by decreased levels of terminal complement components and heightened sC5b-9 complexes (Tanuma et al., 1990; Paixão-Cavalcante et al., 2012; Zhang et al., 2012). C5Nefs can be  detected either as an isolated nephritic factor (~10% of cases) or together with C3Nefs (~40% of cases) (Marinozzi et al., 2017). 

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