MORL Screening Methodology

Enzyme linked immunosorbent assay (ELISA)

  • 1ml frozen EDTA plasma

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  • 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.

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Dense Deposit Disease and C3 Glomerulonephritis
Alternative pathway complement activation generates the active complement breakdown fragment Ba. In the presence of C3b, Factor B (MW: 93 kDa) binds to C3b to form the pre-convertase (C3bB). Factor D cleaves FB, generating the Ba fragment (MW: 33 kDa) and the proteolytic enzyme Bb (MW: 66 kDa). Bb is the catalytically active site of the C3bBb complex (C3 convertase) and is capable of cleaving new C3 to C3a and C3b. C3bBb also recruits available C3b to form the C5 convertase (C3bBbC3b) launching terminal pathway activation. The plasma concentration of Ba is reflective of this activity.

The common pathophysiological basis of both Dense Deposit Disease (DDD) and C3 Glomerulonephritis (C3GN) is dysregulation of the AP complement cascade. Consumption of AP complement components is dependent on the degree of dysregulation of the C3 and C5 convertases. Plasma levels of Ba are elevated in both DDD and C3GN as compared to controls (p<0.001), consistent with consumption of C3 in both diseases.

Information

Quick Facts

  • CPT code: 86160 
  • Test code: 06BAL
  • Turnaround time: 2 weeks
  • Cost: $275
Requisition Form

To order:

Use this requisition form to order this test.

Background Knowledge

Activation of the alternative pathway of complement generates the active complement breakdown fragment Ba. Upon binding with C3b, factor B (MW: 93 kDa) forms the pre-convertase (C3bB). Factor D then cleaves FB, yielding the Ba fragment (MW: 33 kDa) and the proteolytic enzyme Bb (MW: 66 kDa). Bb serves as the catalytically active component of the C3bBb complex (C3 convertase) and is capable of cleaving new C3 into C3a and C3b. Moreover, C3bBb recruits additional C3b leading to the formation of the C5 convertase (C3bBbC3b), thereby initiating terminal pathway activation. The plasma concentration of Ba serves as an indicator of this activity. However, in cases of renal insufficiency, Ba levels are elevated, as the kidney is the primary metabolic site for the Ba and Ba levels may not indicate increased alternative pathway activity. 

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