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Test Code Factor B Factor B Level

Clinical System Name

Factor B Level


Properdin Factor B (Factor B Level)

RIA (Factor B Level)

Properdin Factor B Level

C3PA (Factor B Level)

Complement (Factor B Level)

Sample Requirements

Specimen: Whole Blood

Container(s): Lavender/EDTA

Preferred Vol: 2.0 mL

Minimum Vol: 1.0 mL


Note: Send to the Lab immediately after collection. Must reach lab within one half hour of collection.

Processing Instructions

Reject due to: Thawed Specimen

Spin: Y

Aliquot: Y

Temp: -70 C

Storage location: Centrifuge at room temperature within one half hour of collection; preferably immediately. Transfer the cell-free plasma to an aliquot tube affixed with a large Cerner label. Immediately freeze the cell-free plasma on dry ice or at -70 C. Put specimen in the CPA -70 freezer, Send Outs rack.


Off-site collection: Remove plasma within one half hour of collection, preferably immediately. Transfer 1.0 mL plasma to an aliquot tube and ship frozen. 


Specimen Type Temperature Time
Plasma Room temp  
  Frozen 1 y



STAT Performed TAT
N Varies Up to 4 w


Performing Laboratory

National Jewish Health



National Jewish Health

Complement Laboratory

1400 Jackson Street, Room D411
Denver, CO 80206

Phone Number:

(800) 550-6227



Reference Range


Reference Interval
Human Male: 127.6 - 278.5 mcg/mL
Human Female: 127.6 - 278.5 mcg/mL




Method: Radial Immunodiffusion (RID)

Analytical Volume: 250 mcL


CPT Codes


Send Out Instructions


Reference Test Name: Factor B Level
Reference Test Number: FBL
Instructions: Ship frozen samples Priority Overnight via FexEx and in a well insulated container on dry ice to National Jewish Health Complement Laboratory.