3021225
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Complement Component C2

C-2

Ordering Recommendation

Follow-up test for complement activity screening when CH50 is low or absent and AH50 is normal and high suspicion remains for complement deficiency.

New York DOH Approval Status

This test is not New York state approved. The performing laboratory will submit an NYDOH Single Use Permit (SUP) upon receipt of order. If SUP is approved by NYDOH, testing will be performed.

Specimen Required

Patient Preparation
Collect

Serum separator tube.

Specimen Preparation

Allow specimen to clot for one hour at room temperature. Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP standard transport tube and freeze immediately. (Min: 0.3 mL)

Storage/Transport Temperature

CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.

Unacceptable Conditions

Nonfrozen specimens. Specimens exposed to repeated freeze/thaw cycles. Specimens left to clot at refrigerated temperature.

Remarks
Stability

After separation from cells: Ambient: 2 hours; Refrigerated: Unacceptable; Frozen: 2 weeks

Methodology

Quantitative Immunoturbidimetry

Performed

Mon, Thu

Reported

    5-10 days

Reference Interval

Test Number
 Components
 Reference Interval
  Complement Component 2 13.3-21.6 mg/L

Interpretive Data

Decreased C2 levels may be associated with increased susceptibility to infection (especially pneumococcal infections), systemic lupus erythematosus-like disease, rashes, arthritis, nephritis, and with C1-esterase deficiency. Increased C2 levels are associated with the acute phase response.

Compliance Category

Laboratory Developed Test (LDT)

Note

Hotline History

View Hotline History

 

Hotline History

Date of Change
Test Name Change
Methodology
Performance/Reported Schedule
Specimen Requirements
Reference Interval
Interpretive Data
Note
CPT Code
Component Change
Other Interface Change
New Test
Inactive
10/19/2026
X
N/A

CPT Codes

86160

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Components

Component Test Code* Component Chart Name LOINC
0050148 Complement Component 2 4484-2
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • C2
  • C2 Antigen
  • C2 Level
  • Classical Pathway - Complement
  • complement classical pathway
  • Second componenet of complement
Complement Component C2