Confirmation and characterization of protein S (PS) deficiency: C4b-binding protein elevates as an acute phase protein that may lead to enhanced protein S binding and decreased free protein S levels.
Specimen Sources
Blood, ArterialBlood, CapillaryBlood, Central LineBlood, Venous
Collection: Citrated plasma samples should be collected by double centrifugation. Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio. The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples, except when using a winged blood collection device (ie, "butterfly"), in which case a discard tube should be used. When non citrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Centrifuge for 10 minutes and carefully remove 2/3 of the plasma using a plastic transfer pipette, being careful not to disturb the cells. Deliver to a plastic transport tube, cap, and recentrifuge for 10 minutes. Use a second plastic pipette to remove the plasma, staying clear of the platelets at the bottom of the tube.
Specimen Volume
1 mL plasma (0.5mL min)
Transport Instructions
Frozen plasma
Specimen Stability
8 Hours Room Temperature 14 Days Frozen
Methodology
Enzyme-linked immunosorbent assay (ELISA)
Days Performed
TAT: 5-9 Days
Performing Laboratory
Esoterix Endocrinology
CPT
83520
PDM
5601085
Only Orderable at Locations:
Orderable Everywhere
Results
Component Name
Base Name
Common Name
External Name
C4B BINDING PROTEIN
C4B
C4B BINDING PROTEIN
C4B Binding Protein
Result Interpretation
60 - 130 % Adult levels of C4bBP are generally reached at six months of age. Levels are generally undetectable in the neonate.
