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Protein S Activity
|Test group||Protein S|
|Performed by||UC Davis|
|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.
For patients with Hct's ≥ 55% please contact Hematology (415-353-1747) to obtain blue top tubes with adjusted citrate volumes in order to maintain the proper citrate to plasma ratio for coagulation studies.
|Container type||Blue top filled to full extent of vacuum|
|Amount to Collect||2.7 mL blood|
|Sample type||Citrated plasma|
|Preferred volume||1.5 mL plasma|
|Min. Volume||0.5 mL plasma|
|UCSF Rejection Criteria||Samples collected in outdated blue top vacutainer. Over-filled or under-filled tubes may be rejected Hemolyzed.|
|Processing notes||This test is rarely necessary, most requests for Protein S should be ordered as PRSI unless 'activity' is explicitly included in the test request.
Deliver sample to Hematology ASAP for processing.
Separate and freeze plasma at -20C. Order Quest # 58891P
|Ref Lab Rejection Criteria||Received thawed.|
|Normal range|| Age
|Stability||Room temperature unacceptable, refrigerated unacceptable, frozen at -20C 2 weeks|
|Turn around times||Run once per week. Turnaround 6-10 days|
|Additional information||Test may be useful when there is a normal Free protein S level but persistent clinical suspicion for Hereditary Protein S deficiency.
A Free Protein S Antigen and a Protein S Activity should be ordered on the same specimen when a Protein S activity is requested. If only a Protein S Activity is requested, a Free Protein S Antigen will be performed.
|Last Updated||9/18/2012 2:26:58 PM|
If you have additional questions regarding this test, please call: 415-353-1667