Effective today, September 22nd, 2020, the University of Iowa Hospitals and Clinics core laboratory will change instrumentation used for protein S and protein C testing. Specimen requirements (1.8 or 2.7 mL light blue top tube, full draw) are not changing. The TAT is 1 – 2 days upon specimen receipt in the laboratory.

Protein S Antigen, Free (LAB8982) by immunoturbidimetry is the preferred screening test for protein S deficiency. The reference ranges of this new assay are as follows:

Male: 73 – 139%
Female: 66 – 147%

Protein S activity measurements (Protein S Functional) are still available, but will be mailed out to a reference laboratory with an extended TAT of 2 – 5 days.

Protein C Functional (LAB1133) will continue to be offered in-house, but with a new reference range (≥83%).

Questions should be directed to Anna Merrill, PhD (678-8400, anna-merrill@uiowa.edu) or Sharath Bhagavathi, MD (678-8197, sharathkumar-bhagavathi@uiowa.edu).