MORL Screening Methodology
Enzyme linked immunosorbent assay (ELISA)
- 1ml frozen EDTA plasma
- 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.
Properdin is a single chain plasma glycoprotein (MW: 58 kDa) mainly secreted by white blood cells including monocytes, lymphocytes and neutrophils. It is present in the circulation as a mixture of head-to-tail dimers, trimers and tetramers, with a preponderance of trimers.
Properdin is a positive regulator of the alternative pathway (AP) of complement. In addition to initiating the AP, properdin binds to and stabilizes the C3 convertase, C3bBb increasing its half-life approximately 10 fold. The increased half-life enhances amplification of C3bBb formation, which eventually leads to the formation of the C5 convertase, C3bBbC3b, and initiation of the terminal pathway of complement.
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. While properdin plasma levels are often reduced in both DDD and C3GN, properdin levels are generally lower in C3GN as compared to DDD (p<0.01) (see Zhang et al. Defining the complement biomarker profile of C3 glomerulopathy, CJASN 2014)
Quick Facts
- CPT code: 86160
- Test code: 06PL
- Turnaround time: 2 weeks
- Cost: $330
Background Knowledge -
Properdin is a single-chain plasma glycoprotein (MW: 58 kDa) primarily secreted by white blood cells, including monocytes, lymphocytes, and neutrophils. In circulation, it exists as a mixture of head-to-tail dimers, trimers, and tetramers, with trimers being predominant.
Functionally, properdin acts as a positive regulator of the alternative pathway of complement. Apart from initiating the alternative pathway, it also binds to and stabilizes the C3 convertase, C3bBb, thereby prolonging its half-life by approximately tenfold. The prolonged half-life amplifies the formation of C3bBb, ultimately leading to the generation of the C5 convertase, C3bBbC3b, and triggering terminal pathway activity.
The underlying pathophysiological mechanism of both Dense Deposit Disease and C3 Glomerulonephritis involves dysregulation of the alternative pathway. Consumption of alternative pathway complement components varies depending on the extent of dysregulation of the C3 and C5 convertases. Although properdin plasma levels are typically diminished in both DDD and C3GN, they tend to be lower in C3 Glomerulonephritis as compared to Dense Deposit Disease (p<0.01) (Zhang et al., 2014, Corvillo et al. 2016).
The Clinical Diagnostics Service of the Molecular Otolaryngology & Renal Research Laboratories is a CLIA-approved, Joint Commission-accredited diagnostic laboratory.