C1 Esterase Inhibitor, Functional

Tube Type on ice

Test ID		LAB769
EPIC ORDER		C1 ESTERASE INHIBITOR, FUNCTIONAL
CPT Code(s)		83520
Group/Individual Test		Individual
Laboratory		Core Referral Testing
Tube Station		888
Specimen	Routine:	4 mL blood/Red plain tube on ice/gold SST also acceptable. See important comments
	micro:	1.2 mL blood
Availability	Routine:	Reference Laboratory - Mayo Clinic Laboratories
	STAT:	N/A
Turnaround Time		5-7 days
Reference Range	Normal:	See separate report
Comments		Deliver immediately: Sample must be spun, aliquoted, and frozen within 30 minutes of collection. Patient should be fasting (12 hour fast preferred). Patients being investigated for a deficiency of C1 Esterase Inhibitor can be effectively screened with serum concentration of C4. A C4 within the reference range has a 99% negative predictive value for the diagnosis of C1 esterase inhibitor deficiency (Gompels MM, Lock RJ, Morgan JE, et al. A multicentre evaluation of the diagnostic efficiency of serololgical investigations for C1 inhibitor deficiency. J Clin Pathol 2002; 55:145-147)

Reviewed by J. Carr on October 30, 2025

UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514