Test Directory

Complement deficiency can lead to life-threatening infections well as long-term autoimmune conditions such as systemic lupus erythematosus (SLE) and hereditary angioedema (HAE). The AH50 hemolytic assay is a sensitive method for detection of total alternative complement activity or lack thereof. Severe or recurrent infections that produce strong activation of the alternative complement pathway may lower AH50 levels below normal. Genetic or acquired complement deficiency involving the alternative complement pathway components (Factor B, Factor D, Properdin, and C3) as well as terminal complement components (C5, C6, C7, C8, and C9) may lower AH50 levels. Severe or recurrent infections that produce strong activation of the alternative complement pathway may lower AH50 levels below normal. The AH50 assay can also be utilized to monitor response to anti-complement therapies

Specimen Type: Serum

Collection Container: Red Top, Plain

Desired Specimen Volume: 1 mL

1. Collect a red top, plain tube via venipuncture.

Complement activity is very labile and reliable results depend on correct handling of the specimen.

1. Allow specimen to clot for no longer than 30 minutes, then immediately separate serum from cells.
2. Immediately after separation from cells, transfer 1 mL of serum to a clear aliquot tube (screw cap).
3. Sample MUST be processed and frozen within one hour of collection.

Transport to the laboratory frozen.

• Gel barrier tubes

See patient report.

• Alternative Complement Pathway Activity (AH50)
• TSO - AM50
• TSO - Compliment (ACP)