Laboratory hours: Monday-Friday: 7 am – 5 pm; Saturday: 10 am – 2 pm.
For consultation, contact the physician covering coagulation at (612) 273-4797.
Please follow the tips below to maintain specimen integrity and ensure valid coagulation results.
Coagulation samples are collected in 3.2% buffered citrate
(light blue-top tubes).
The blood sample should be obtained from a clean venipuncture. Traumatic collections may result in an activated or clotted specimen. Avoid using needles smaller than 23 gauge. Avoid leaving the tourniquet on the patient’s arm for an extended period prior to the collection.
Do not use the first 2 mL of blood collected for coagulation testing.
Fill light blue-top tubes as far as vacuum will allow and mix by gentle inversion.
When tube cannot be filled by vacuum, for correct anticoagulant to blood ratio, fill to indicator line on tube
2.7 mL blood in 3.0 mL tube, or 1.8 mL blood in 2.0 mL tube). It is critical that the tube be filled to indicator line for proper plasma to anticoagulant ratio.
NOTE MINIMUM TEST VOLUMES:
• One 2.0 mL blue top tube (1.8 mL blood) is sufficient for 1-2 tests (excluding a Lupus Battery or a von Willebrand Screen or Panel).
• One 3.0 mL blue top tube (2.7 mL blood) is sufficient for 3-4 tests (excluding a Lupus Battery or a von Willebrand Screen or Panel).
• Three 3.0 mL blue top tubes (2.7 mL blood in each) are sufficient for tests that might logically be collected in a single collection.
Examples:
 Testing for abnormal bleeding (which would include a von Willebrand Factor Screen or Panel)
 Testing for abnormal clotting (which would include a Lupus Battery , Antithrombin, Protein C and/ or Protein S)
Note: Platelet function closure time (PFCT) requires a unique 3.0 mL tube (2.7 mL blood).
Thromboelastography (TEG) requires a unique 3.0 mL tube (2.7 mL blood). A 4 mL green-top heparin tube- no gel (4 mL blood) collected at the same time is required if the study includes platelet mapping.
Collect samples from patients with hematocrit values greater than 55% in a special tube, obtained from the laboratory.
Anticoagulants may interfere with clotting based assays. Direct thrombin inhibitors should be stopped 12-
24 hours from IV and 3 days for dabigatran. Direct anti-Xa drugs (rivaroxaban, apixaban, edoxaban) should be stopped 3 days prior to testing.
After Care : If the patient has a coagulation abnormality, apply direct pressure to the puncture site for 10 minutes; apply a pressure dressing. Instruct the patient to leave the bandage on for 12 hours.
Check tubes for gross clots by inverting the tube.
If the volume in the tube is less than 1.8 mL in a 2 mL tube or less than 2.7 mL in a 3 mL tube, call the provider, cancel and credit with DEL-USUNDR-;person called, date, tech initials. DEL=Canceled, Test credited. USUNDR=Unsatisfactory specimen, tube underfilled.
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Due to degradation of coagulation factors in blood after samples are collected, prompt processing is required to ensure the integrity of the sample. All specimens for Special Coagulation laboratory must be received and processed according to the special instructions.
Special Instructions:
The following tests must be shipped at room temperature to arrive at UMMC within 4 hours of collection.
If more than 4 hours is required for transport, the specimen must be processed as defined in the
Processing section (below):
1. Activated Protein C Resistance (APCR)
2. Antithrombin Chromogenic (ANTCH)
3. Bethesda Assay for Factor 8 (BETH2)
4. Bethesda Assay for Factor 9 (BETH4)
5. Factor 10 Chromogenic (F10CH)
6. Factors: Factor 2 (F2), Factor 5 (F5), Factor 7 (F7), Factor 10 (F10), Factor 8 (F8),
Factor 9 (F9), Factor 11 (F11) , Factor 12 (F12) , and/or Factor 13 Antigen (F13A)
7. Heparin Induced Thrombocytopenia (HIT)
8. Lupus Battery (LUPUSB)
9. Plasminogen Chromogenic (PLASCH)
10. Protein C Chromogenic (PCCH)
11. Protein S Free (PSF)
12. PTT Mixing studies (PTT1T2)
13. Reptilase (REPT)
14. Ristocetin Cofactor (RI)
15. Thrombin Time (TT)
16. Von Willebrand Factor Activity (VWACT)
17. Von W illebrand Factor Antigen (VWA)
18. Von Willebrand Factor Multimers
The tests below must be shipped at room temperature to arrive at UMMC within 3 hours of collection. If more than 3 hours is required for transport, the specimen must be processed as defined in the
Processing section (below):
1. Arixtra (ARIX)
2. Prothrombin Fragment 1.2 (PF) – after processing is complete, aliquot 2 tubes for the
Prothrombin Fragment 1.2 assay.
Processing:
1. Centrifuge samples to obtain platelet poor plasma suitable for plasma coagulation assays using a method validated by the processing laboratory according to CLSI recommendations [CLSI.
Collection, Transport, and Processing of Blood Specimens for Testing Plasma-Based
Coagulation Assays and Molecular Hemostasis Assays; Approved Guideline-Fifth Edition. CLSI document H21-A5. Wayne, PA; Clinical Laboratory Standards Institute, 2008]. Platelet poor plasma has a platelet count of less than 10x10
9
/L (10,000/microliter). The sample should be maintained at room temperature during processing. The optimum centrifugal speed and duration must be established by the processing laboratory due to differences in equipment within laboratories. a. A common method is 1500g for no less than 15 minutes at room temperature. b. Higher speed and shorter duration centrifuges may be suitable; however, the referring laboratory must determine the optimum conditions for producing platelet poor plasma.
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2. Remove the lipid-free, platelet poor plasma that is to be frozen and aliquot into patient labeled polypropylene tubes with a piece of clear tape wrapped around the patient label: a. If there is ~2-3 mL of platelet free plasma, aliquot into 2-3 tubes. b. If there is limited platelet free plasma (~1 mL), try to aliquot it into 2 tubes.
If there is <1 mL of plasma, then aliquot all into 1 tube. c. If there is >4 mL of platelet free plasma, aliquot into at least 3 tubes.
3. Immediately place the tubes in a container with dry ice or in a –70 o
C freezer until completely frozen. If the laboratory only has a –20 o
C freezer, then place the lipid-free, platelet poor plasma in that freezer (note: specimens can only be stored for up to 2 weeks in a –20 o
C freezer). Send frozen sample on dry ice.
UMMC Outpatient: Send whole blood samples to Acute Care Laboratory (see TEG procedure for specimen handling with tubes for TEG testing).
Specimen Management: During lab hours place processed sample in Special Coag dry ice cooler. After hours, immediately place on dry ice in grey dry ice chest or in –70 o
C freezer.
Notify Special Coag if: 1) unprocessed specimen is received that was collected beyond the recommend time, or 2) whole blood is received frozen.
Samples that are received frozen should be kept on dry ice or at –70 o
C until tested.
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