Atypical Hemolytic Uremic Syndrome complement panel, serum and plasma

Alphabetical Test listing

Atypical Hemolytic Uremic Syndrome complement panel, serum and plasma-994

Test name:

Test number:

994

Excellian order number:

LAB994

Abbreviation:

MSO

Alternate names:

aHUS
HUS
Factor B
Factor H
CBb Complement
SC5b-9 Complement

Useful for:

Detecting deficiencies in the alternative pathway that can cause atypical-hemolytic uremic syndrome, dense deposit disease, and C3 glomerulonephritis
A second-order test that aids in the differential diagnosis of thrombotic microangiopathies

Patient preparation information:

Fasting preferred
- Fasting for a blood test
Do not collect specimens for at least 48 hours following plasma exchange.

Specimen type:

EDTA plasmaand serum

Collection container:

Lavender (EDTA), 4mL

AND

Gold serum separator (SST) tube

Volume:

1.5 mL EDTA plasmaand 1.75 mL serum

Minimum volume:

1.5 mL each, EDTA plasma and serum

Collection instructions:

Immediatley following collection, mix sample by gentle inversion 3 - 4 times to prevent clotting
Place tube on wet ice immediately after specimen collection

Processing instructions:

Plasma:

Spin at 4^◦ C in a refrigerated centrifuge
Transfer plasma to two (2) Screw cap transfer vial/tubes (Mayo T914), each containing 0.75 mL labelled as EDTA plasma
Freeze within 30 minutes

Serum:

Allow serum sample to clot while on wet ice
Spin at 4^◦ C in a refrigerated centrifuge
Transfer serum into three (3) Screw cap transfer vial/tubes (Mayo T914), labelled as serum
Freeze within 30 minutes

NOTE: If a refrigerated centrifuge is not available, it is acceptable to use a room temperature centrifuge, provided the sample is kept on ice before centrifugation, and frozen immediately afterward

Transport container:

Five (5) Screw cap transfer vial/tube (Mayo T914) (3) labelled as serum and (2) labelled as EDTA plasma

Plasma: 2 separate plastic vials:
each containing 0.75 mL

Serum: Aliquot serum into 3 separate plastic vials:
a. Aliquot 0.5 mL into a plastic vial labeled COM3
b. Aliquot 0.5 mL into a plastic vial labeled
C3HUS/C4HUS/FBCA/FHCA
c. Aliquot 0.75 mL into a plastic vial labeled AH503

Alternate specimen type:

Sodium citrate (NaCit) plasma and serum

Alternate collection container:

Lt blue Sodium citrate (NaCit)

Red serum vial/tube, 5 mL

Transport and stability:

Frozen (strict) - 14 days

Reason for rejection:

Gross hemolysis and lipemia

Performing lab:

Mayo Clinic Laboratories (AHUSD): R-NX

Days set up:

Varies

TAT:

12 - 21 days

Method:

C3HUS, C4HUS, FBCA, FHCA, C5AG2: Nephelometry

COM3: Automated Liposome Lysis Assay

AH503, C4D, CBB, SC5B9: Enzyme-Linked Immunosorbent Assay (ELISA)

Reference ranges:

An interpretive report will be included

Factor B complement Ag:                                     15.2-42.3 mg/dL
SC5b-9 complement:                                                  ≤250 ng/mL
Factor H complement Ag: 18.5-40.8 mg/dL
CBb complement activation fragment:                          ≤1.6 μg/mL
Complement C4:                                                        14-40 mg/dL
Complement C3:                                                       75-175 mg/dL
Complement, alternate pathway (AH50), functional:      ≥46% normal
Complement, total:                                                      30-75 U/mL

Reference values have not been established for patients who are <16 years of age.

CPT codes:

86160 x 6
86161
86162

Date created:

09/04/2019

Revised date:

08/31/2026

Review date:

03/11/2025