Plasma Complement Ba Fragment Report

Test Code
11372


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


Transport Temperature
Frozen (-80° C)


Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen (-80° C): Indefinitely


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Thawed OR unlabeled samples will be REJECTED for testing


Methodology
Enzyme-Linked Immunosorbent Assay (ELISA)

Setup Schedule
Set up: Mon-Fri; Report available: 14 days


Reference Range
Normal


Clinical Significance
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.

Indications for screening: Screening is appropriate for patients with DDD and C3GN.




The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.