C1 Esterase Inhibitor Functional assay (Blood)

Testing Laboratory

Auckland Te Toka Tumai | Auckland Hospital

Department

Immunology

Delphic Registration Code (Alpha Code)

INHF

Test Code (Numeric Code)

7233

Laboratory Handling

Phlebotomy

Samples must be collected Monday-Friday between 08:00 and 14:30. Apply an urgent sticker and clearly write "C1 esterase inhibitor function". Contact Ichem staff on 09 307 4949 ext. 22113 immediately after collection to alert the laboratory.

Transport

Ambient

Registration

Ichem staff provide registration staff with a tracking form containing patient details and the time of collection before the sample arrives. On arrival, Lamson staff time stamp the sample and immediately deliver the sample, request form and tracking to registration. Register the sample immediately and pass it along to Immunochemistry. After hours the sample must be given to the Cabinet staff. Cabinet staff to centrifuge the sample immediately. Prepare two aliquots. Freeze aliquots at -20°C.

Separating

Serum must be separated within 1 hour of collection. immediately freeze the separated serum at -20°C to maintain sample integrity.

Laboratory

LabPlus Immunochemistry

Test Adds Requirement

Test adds of other complement assays on this request is not recommended.

Sample Stability

Must be stored within 1 hour of collection. Freeze at -20°C immediately after separation. Long term storage at -20°C.

Synonyms

INHF, C1 INH Function

Turnaround Time

2 weeks

Test is performed on a Tuesday or Thursday.

Specimen Type

  • Serum

Specimen Requirements

Tube/Container Type:

Preferred
  • SST II (Gold Cap)
Acceptable
  • Plain (Red Top)
Preferred Sample Volume (ml)

3.5

Minimum Sample Volume (ml)

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred
  • SST II (Gold Cap)
Acceptable
  • Plain (Red Top)
Preferred Sample Volume (ml)

1

Minimum Sample Volume (ml)

1

Pre-testing Requirements

Screening for acquired or hereditary C1 inhibitor deficiency will now be undertaken with a functional C1 inhibitor assay and a C4 assay. If the C1 inhibitor functional assay is reduced, the C1 antigenic assay will be added to testing. If there is high suspicion about C1 inhibitor deficiency in spite of a normal C1 inhibitor functional assay, please contact the Immunology team at LabPlus.

Last updated: 05/05/2026