Item Value
Test name Protein S, free
Available Stat? No
Turn around times 2-4 weeks
Performed by Parnassus Hematology
Normal range
> 6 mo 53-137%


There is no published pediatric reference range for Free Protein S antigen, which generally parallels the level of Total Protein S antigen, and from which the pediatric (< 6 months old) reference ranges given below are derived.

Full Term Infant
Day 1 Day 5 Day 30 Day 90 Day 180
12-60% 22-78% 33-93% 54-118% 55-119%


From: Andrew M et al. Development of the Human Coagulation System in the Full Term Infant. Blood. 1987, 70: 165- 172

Healthy Premature Infant
Day 1 Day 5 Day 30 Day 90 Day 180
14-38% 13-61% 22-90% 40-112% 44-120%


From: Andrew M, et al. Development of the Human Coagulation System in the Healthy Premature Infant. Blood November 1988, 72(5): 1651-1657.
Container type Blue top filled to full extent of vacuum
Amount to Collect 2.7 mL blood
Collection Instructions 1. Check the expiration date on the label of the blue top vacutainer before drawing the patient.

2. For blood collection in a sodium citrate blue top, the tube must be filled to above the Minimum Fill Indicator on the tube. It is crucial to wait and allow the tube to stop filling before removing it from the needle.

3. With use of a butterfly needle, draw about 1 cc using a separate blue top to remove air from tubing, discard the first tube and then draw a second blue top tube filled to the full extent of the vacuum.

4. Tubes should not be filled past the Maximum Fill dashed line by either using a syringe or removing the tube cap.

Draw only before institution of oral anticoagulant therapy or after a stable therapeutic regimen has been established.
Sample type Citrated plasma

If you have additional questions regarding this test, please call: 415-353-1667