Alternative Complement Pathway Activity (AH50)

Casandra

Casandra Test Code AR29905Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 2005373CPT Code 86161

Alternative Complement Pathway Activity (AH50)

Also known as: AH50

Clinical Use

Order Test

Use

The Alternative Complement Pathway Activity (AH50) test is used for the initial screening of suspected deficiencies in the alternative complement pathway, which can indicate inherited or acquired deficiencies in complement components or secondary consumption processes. Abnormal activity in this pathway may be associated with various conditions, including atypical hemolytic uremic syndrome, C3 glomerulonephritis, dense-deposit disease, and atypical postinfectious glomerulonephritis.

Special Instructions

Not provided.

Limitations

This test has not been cleared or approved by the U.S. Food and Drug Administration. It is laboratory-developed, and its performance was determined by ARUP Laboratories. Interpretations of low AH50 with normal CH50 can indicate specific pathway defects, while normal AH50 with low CH50 suggests defects in the classical pathway. If results are inconsistent or unexpected, repeat testing with freshly frozen serum is advisable.

Test Details

New York Approved

Methodology

Immunoassay (ELISA)

Biomarkers

Alternative Complement Pathway Activity

Analyte

Alternative Complement Pathway Activity

Concentration / Level • Categorical (e.g., Positive / Negative / Indeterminate)

LOINC Codes

Result Codes

74520-8

Result Turnaround Time

7-14 days

Specimen

Serum

Volume

Not provided

Minimum Volume

0.3 mL

Container

Plain Red

Collection Instructions

Allow specimen to clot for one hour at room temperature. Separate serum from cells ASAP and centrifuge at 2-8 degrees C and aliquot serum into ARUP standard transport tube.

Storage Instructions

Freeze specimen immediately at -70 degrees C or lower.

Causes for Rejection

Specimen types other than serum collected from RED TOP tubes. SST or serum gel tubes are not acceptable. Refrigerated or room temperature specimens. Specimens left to clot at refrigerated temperature. Specimens exposed to repeated freeze/thaw cycles. Grossly hemolyzed or grossly lipemic specimens or icteric specimens.