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Plasma Complement Bb Fragment Report
Test Code11373
CPT Codes
86160<br>This test is not available for New York patient testing<br>Restricted Client Code
Preferred Specimen
1 mL plasma collected in an EDTA (lavender-top) tube
Patient Preparation
PLEX treatments will affect tests, please wait approximately 14 days after PLEX to draw samples.
Minimum Volume
1 mL
Instructions
All plasma samples MUST be processed and frozen down to -80° C immediately after collection (please see instructions).
Sample type must be clearly labeled (plasma) and shipped out overnight on at least 5 lb dry ice (Monday-Thursday).
1.) Follow standard phlebotomy techniques to collect at least 6 cc of whole blood drawn in an EDTA or Citrate vacutainer tube.
2.) Allow the blood in the EDTA or Citrate tube to clot at room temperature for 30 minutes.
3.) Centrifuge the clotted blood at room temperature (1000 x g for 10 minutes).
4.) Label "EDTA" or "Citrate" on clean screw top-tube(s).
5.) Pipette cell-free supernatant (at least 2 mL) to each labeled tube(s).
6.) Place the tube immediately at -80°C (or on dry ice). Sample must remain deep frozen.
Plasma must be frozen and U.S. samples must be shipped OVERNIGHT with a minimum of 3 kg (or 6 lb) dry ice.
-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.
-Delivery: Monday-Friday. NO WEEKEND DELIVERIES
ALL requested information must be provided or testing will not be performed
Patient information:
-Patient date of birth and gender
-Patient ethnicity and race
-Patient's clinical information and family history of kidney disease
Specimen information:
-Patient identifiers (full name, date of birth, sex and medical record number)
-Date of collection
-Sample type-frozen samples must be CLEARLY LABELED as plasma (and type, EDTA or Citrate)
-Ordering physician
Sample type must be clearly labeled (plasma) and shipped out overnight on at least 5 lb dry ice (Monday-Thursday).
1.) Follow standard phlebotomy techniques to collect at least 6 cc of whole blood drawn in an EDTA or Citrate vacutainer tube.
2.) Allow the blood in the EDTA or Citrate tube to clot at room temperature for 30 minutes.
3.) Centrifuge the clotted blood at room temperature (1000 x g for 10 minutes).
4.) Label "EDTA" or "Citrate" on clean screw top-tube(s).
5.) Pipette cell-free supernatant (at least 2 mL) to each labeled tube(s).
6.) Place the tube immediately at -80°C (or on dry ice). Sample must remain deep frozen.
Plasma must be frozen and U.S. samples must be shipped OVERNIGHT with a minimum of 3 kg (or 6 lb) dry ice.
-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.
-Delivery: Monday-Friday. NO WEEKEND DELIVERIES
ALL requested information must be provided or testing will not be performed
Patient information:
-Patient date of birth and gender
-Patient ethnicity and race
-Patient's clinical information and family history of kidney disease
Specimen information:
-Patient identifiers (full name, date of birth, sex and medical record number)
-Date of collection
-Sample type-frozen samples must be CLEARLY LABELED as plasma (and type, EDTA or Citrate)
-Ordering physician
Transport Temperature
Frozen (-80° C)
Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen (-80° ): Indefinitely
Refrigerated: Unacceptable
Frozen (-80° ): Indefinitely
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Thawed OR unlabeled samples will be REJECTED for testing
Methodology
High Performance Liquid Chromatography • Enzyme-Linked Immunosorbent Assay (ELISA)
FDA Status
This test was developed and its performance characteristics determined by the Clinical Diagnostics Division of the Molecular Otolaryngology & Renal Research Laboratories. It has not been cleared or approved by the US Food and Drug Administration.
Setup Schedule
Set up: Mon-Fri; Report available: 28 days
Reference Range
Negative
Clinical Significance
Complement Bb Fragment Level Assay
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).
Indications for screening: Screening is appropriate in patients with complement-mediated renal diseases
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).
Indications for screening: Screening is appropriate in patients with complement-mediated renal diseases
