C1 Esterase Inhibitor antigenic assay (Blood)

Testing Laboratory

Auckland Te Toka Tumai | Auckland Hospital

Department

Immunology

Delphic Registration Code (Alpha Code)

INHA

Test Code (Numeric Code)

7232

Laboratory Handling

Phlebotomy

All specimens requiring the C1 esterase inhibitor functional assay should only be collected between 8am AND 2.30pm MON - FRI. At the time of collection, place an "Urgent" label on the form and indicate below the sticker "C1 Esterase". Contact ICHEM on 09 307 49 49 ext 22113 to inform the laboratory of the collect. It is crucial that the laboratory staff separate the sample within 1 hour of collection and freeze the serum at -20°C

Transport

Ambient

Separating

C1 Esterase Inhibitor Functional Assay needs to be separated and frozen within an hour of collection. All C1 Esterase requests also require an aliquot for C4.

Laboratory

LabPlus Immunochemistry

Test Adds Requirement

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

Sample Stability

-20°C for one month - repeat freeze thaw cycles should be avoided. 2-8°C for 8 days if this is not reflexed from the C1 esterase functional assay.

Associated Tests

• C1 Esterase Inhibitor Functional assay (Blood)

Synonyms

C1 esterase, C1 functional

Turnaround Time

2 weeks

This is a reflex test for an abnormal C1 esterase functional result.

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

From 3 July 2017:
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.

Aliquot Instructions

Sample Type

• Serum

Minimum Volume (ml)

3.5

Transport to Lab

Frozen

Additional Referral/Aliquot Information

Once the sample has clotted, centrifuge the sample at 3000 rpm for 5 minutes.
Separate the serum into two tubes and label the tubes with the patient details.
Freeze the aliquots at -20°C.
Place an urgent sticker on the request form and write C1 Esterase Inhibitor on it.
Transport the sample aliquots at -20°C.

All C1 Esterase requests also require a separate aliquot for C4 to prevent erroneous results for the C1 Esterase assay due to repeated freeze/thawing

Test Method

Turbidimetry (Optilite)

Limitations / Interference

Turbidimetric assays are not suitable for measurement of highly lipaemic or haemolysed samples or samples containing high levels of circulating immune complexes (CICs).

Uncertainty of Measurement

12%

Contact Information