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Test Code C4 Complement C4

Specimen and Container/Tube

Specimen Type: Plasma

Preferred Specimen: Li-Heparin Mint Green Top

Other Acceptable specimens: Serum/Gold Top, Serum/Red Top

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

Collect specimen per standard collection procedure and send to laboratory immediately. 

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Samples should be centrifuged within 2 hours of collection.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Aliquot sample into plastic transport tube containing a minimum of 0.2 mL of specimen.
  • Samples must be sent room temperature at 15-25oC.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are clotted or grossly hemolyzed.
  • Specimens that were transported unspun/whole blood and draw time is greater than 6 hours.

Reference Values

 

Test

Age

Sex

Reference Range

C4

<1 Month

All

7-27 mg/dL

C4

1 Month to 10 Years

All

7-41 mg/dL

C4

>10 Years

All

18-45 mg/dL

Note: Reference range based on in-house studies, recommendations from Tietz Textbook of Clinical Chemistry, and Roche product literature. 

Critical Values

Analyte

Unit

Low

High

Age

N/A

N/A

N/A

N/A

N/A

CPT Codes

86160

LOINC Codes

4498-2

Volume

Preferred Volume: 0.5 mL

Minimum Volume: 0.2 mL

Specimen Stability

Storage Temperature

Stability

Room temperature

2 days

Refrigerated

8 days

Frozen

3 months

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

Test Components

Complement Factor C4
 

Clinical Indications

Useful as an aid in the diagnosis of C4 deficiency. Complement factor C4 participates in activation by the classical route of the complement system.

Methodology

Immunoturbidimetric Assay (Roche Diagnostics)

Additional Information

  • Results should always be assessed in conjunction with patient's medical history, clinical examination and other findings.
  • C4 is an acute phase protein and is produced to an increased extent during inflammatory processes. It is elevated in systemic infections, noninfectious chronic inflammatory conditions (primarily chronic polyarthritis) and physiological states (pregnancy).

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

 

STAT Turnaround Time: Not available as STAT test

Routine Turnaround Time: 4 hours

Testing Schedule: 24/7

Synonyms/Keyword Search

C4 (4th Component of Complement), Complement C4

Last Review Date

8/19/2024