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Lab Manual for Moffitt-Long and Mount Zion

Lab Manual for SFGH

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Factor 11 Activity

Item Value
Approval req'd? No
Available Stat? No
Test code F11
Test group Coagulation Factor Activities
Performed by Parnassus Hematology
In House Availability Test run 0800-1500 Monday-Friday

Note: If testing is needed outside of these hours, contact Hematology at 3-1747.
Method Clotting assay (Stago - STAR)
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.

Deliver immediately to the laboratory.

For patients with Hct's ≥ 55% please contact Hematology (x3-1747) 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 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UCSF Rejection Criteria Samples collected in outdated blue top vacutainer.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
Processing notes Provide sample(s) to Hematology section asap.
Units %
Normal range
Day 1 10-66%
Day 5 23-87%
Day 30 27-79%
Day 90 41-97%
Day 180 38-134%
≥ 18 year old 72-161%


Pediatric Reference (Day 1 – 180): Andrew, M et al. Development of the human coagulation system in the full-term infant. Blood. 70:165-72).
Synonyms FXI; F11; Factor XI
Stability Factor assays should generally be performed within four hours of specimen collection or the plasma frozen; the latter is stable for 2 weeks at -20C or 6 months at -70C.
Turn around times 1-3 days
Additional information If unusual findings are noted a pathologist review and interpretation may be performed and separately billed for
LOINC code 3226-8
Last Updated 4/1/2014 11:34:34 AM
Entry Number 367

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

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