MORL Screening Methodology
The C3 Convertase Stabilizing Assay (C3CSA) assesses the capability of C3Nefs to stabilize C3 convertase formed on sheep erythrocytes.
- 1ml frozen serum
- 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.
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).
Quick Facts
- CPT codes: 86161
- Test code: 06C3NEF
- Turnaround time: 4 weeks
- Cost: $250
Background Information
C3 nephritic factors (C3Nefs) are IgG autoantibodies that target C3 convertase (C3bBb). They were first identified by Spitzer and colleagues in 1969 as substances in patient serum persistently activating the alternative pathway cascade (Spitzer, 1969). These autoantibodies disrupt the innate mechanisms that typically regulate C3 convertase activity. They are detectable in up to 80% of patients with Dense Deposit Disease (DDD) and in approximately 50% of patients with C3 glomerulonephritis (C3GN) (Zhang, et al. 2012). Nephritic factors can also be found in patients with partial lipodystrophy, meningococcal meningitis, post-streptococcal acute glomerulonephritis, and immune-complex membranoproliferative glomerulonephritis (Savage et al., 2009; Fremeaux-Bacchi et al., 1994; Hulton et al., 1992; Nicolas et al., 2014; Niel et al., 2015; Michels et al., 2018).
The Clinical Diagnostics Service of the Molecular Otolaryngology & Renal Research Laboratories is a CLIA-approved, Joint Commission-accredited diagnostic laboratory.