Ristocetin Induced Platelet Aggregation
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Turnaround Time:
1 day
Test Schedule:
Advance notice required. Call 503-494-7383 to schedule. Performed Monday through Friday, 8:30 AM to 12:00 PM with preference for Tuesday/Wednesday.
Specimen Requirements:
Two full 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate, AND one 3 mL LAVENDER (EDTA) top whole blood tube. Do NOT send in pneumatic tube system. Do NOT spin. Stability is 3 hours at room temperature.
Fasting samples preferred. Rarely, food interferences are possible. Avoid aspirin for 7 days prior to test and non-steroidal anti-inflammatories at least 2 days before the test. Schedule with Client Services, 503-494-7383, no more than 2 per day, preferred Tuesday and Wednesday before noon.
Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.
OHSU clinics must cab specimen to the H&T Lab, Dillehunt Hall, Room 3050 if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-8445.
Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.
Pediatric Specimen Requirements:
Two full adult size 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate, AND one PEDIATRIC LAVENDER top tube. Do NOT send in pneumatic tube system. Do NOT spin. Stability is 3 hours at room temperature.
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Von Willebrand Panel
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Includes:
Factor VIII Activity, Von Willebrand Factor Activity, Von Willebrand Antigen
Turnaround Time:
1 to 3 days
Test Schedule:
Batched 1 to 2 times per week. Call 503-494-7383 if STAT.
Critical Values:
See individual tests.
Specimen Requirements:
Four full 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.
OHSU clinics must cab specimen to the Core Lab, Hatfield Research Center, 9th Floor (room 9D10) if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-7383.
Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.
For referral testing, submit four tubes, each with 1.0 mL frozen platelet poor citrated plasma.
Pediatric Specimen Requirements:
Two full pediatric 1.3 mL LIGHT BLUE top tubes, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
Prepare 3 aliquots:
FVIII: 500 microliters
vWF: 100 microliters
vWAg: 500 microliters
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Reference Range:
See individual tests.
For children less than 6 months, see link to published reference ranges (Opens in a new window).
Comments:
This test is used in the diagnosis and classification of von Willebrand disease.
The von Willebrand factor (vWF) is absent or decreased in individuals with von Willebrand disease (vWD). vWF activity is the functional measure of the factor VIII molecule that is necessary for the agglutination of platelets observed in the presence of ristocetin. Since many variants of vWD exist, the yield of identifying patients with this disease is enhanced if all three of the following are assayed: factor VIII activity, von Willebrand factor antigen (vWF:Ag), and vWF-RCT activity. Because many patients with vWD have mild disease, repeated testing may be necessary to diagnose this disorder. Normal values do not exclude vWD. Female patients with vWD on oral contraceptives or who are pregnant may have normal values. Von Willebrand factor is also an acute-phase reactant and is elevated with stress or exercise.
Methodology: Refer to specific assays.
High doses of standard heparin (greater than 1.0 U/mL) may interfere with a PT mixing study. Anti-Xa agents such as Rivaroxaban may also interfere with PT mixing studies. Clinical correlation is advised.
Synonyms:
Von Willebrand
Von Willebrand Factor Antigen Assay
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Includes:
This assay is included in Von Willebrand Panel.
Turnaround Time:
1 to 3 days
Test Schedule:
Run 2 to 3 times per week.
Units:
Critical Values:
Less than 19%
Specimen Requirements:
One full 2.7 mL LIGHT BLUE top tube, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.
OHSU clinics must cab specimen to the H&T Lab, Dillehunt Hall, Room 3050 if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-8445.
Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.
For referral testing, submit one tube with 1.0 mL frozen platelet poor citrated plasma.
Pediatric Specimen Requirements:
One full pediatric 1.3 mL LIGHT BLUE top tube, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Reference Range:
42% to 176%
Comments:
This test is used in the diagnosis, classification, and treatment of von Willebrand disease.
Von Willebrand disease is characterized by easy bruising or prolonged bleeding from mucosal surfaces due to reduced vWF concentration (Type I), qualitative dysfunction (Type II) or complete loss of production (Type III). Both quantitative and qualitative (functional) assays are required for the diagnosis and appropriate therapeutic intervention. Because many patients with vWD have mild disease, repeated testing may be necessary to diagnose this disorder. Normal values do not exclude vWD. Female patients with vWD on oral contraceptives or who are pregnant may have normal values. Von Willebrand factor is also an acute-phase reactant and is elevated with stress or exercise.
Methodology: Immunoturbidometric assay.
Synonyms:
VWF AG
Von Willebrand Factor Activity
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Includes:
This assay is included in Von Willebrand Panel.
Turnaround Time:
1 to 3 days
Test Schedule:
Batched 1 to 2 times per week. Call 503-494-7383 if STAT.
Units:
Critical Values:
Less than 19%
Specimen Requirements:
One full 2.7 mL LIGHT BLUE top tube, 3.2% sodium citrate, OR two 1 mL frozen sodium citrate plasma aliquots. Separate and freeze plasma. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.
OHSU clinics must cab specimen to the H&T Lab, Dillehunt Hall, Room 3050 if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-8445.
Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.
Pediatric Specimen Requirements:
One full pediatric 1.3 mL LIGHT BLUE top tube, 3.2% sodium citrate, OR two 0.5 mL frozen sodium citrate plasma aliquots. Separate and freeze plasma. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Reference Range:
40% to 130%
For children less than 6 months, see link to published reference ranges (Opens in a new window).
Comments:
This test aids in diagnosis of von Willebrand disease.
Von Willebrand disease is characterized by easy bruising or prolonged bleeding from mucosal surfaces due to quantitative (Type I) or qualitative (Type II) vWF deficiency. Both quantitative and qualitative (functional) assays are required for the diagnosis and appropriate therapeutic intervention. Because many patients with vWD have mild disease, repeated testing may be necessary to diagnose this disorder. Normal values do not exclude vWD. Female patients with vWD on oral contraceptives or who are pregnant may have normal values. Von Willebrand factor is also an acute-phase reactant and is elevated with stress or exercise.
Methodology: Turbidometric Enzymeimmunoassay.
This test was developed and its performance characteristics determined by OHSU.The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.
The clinical significance of vWF activity levels between 0.3 to 0.5 U/mL is unclear and clinical correlation is required. See NHLBI von Willebrand Disease Expert Panel Guidelines:
https://www.nhlbi.nih.gov/health-pro/guidelines/current/von-willebrand-guidelines/full-report/1-intro.htm (Opens in a new window)
Protein C Activity, Reflex INR
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Includes:
INR is reflexed on patients with a low Protein C level.
Turnaround Time:
3 to 5 days
Test Schedule:
Batched 2 times per week.
Units:
Interpretation:
Non-coumadin anticoagulants may falsely elevate Protein C values, even when the concurrent PTT is normal.
Specimen Requirements:
Two 2.7 mL blood, LIGHT BLUE top tubes, 3.2% sodium citrate OR two 1 mL frozen sodium citrate plasma aliquots. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.
OHSU clinics must cab specimen to the H&T Lab, Dillehunt Hall, Room 3050 if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-8445.
Detailed instructions are included in this manual under Specialized Lab Services, Hemostasis & Thrombosis (Opens in a new window) section.
Pediatric Specimen Requirements:
Two full pediatric 1.3 mL LIGHT BLUE top tubes, 3.2% sodium citrate, OR two 0.5 mL frozen sodium citrate plasma aliquots.
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Reference Range:
70% to 140%
For children less than 6 months, see link to published reference ranges (Opens in a new window).
Comments:
This test aids in the diagnosis of patients at risk of venous thromboembolic disease.
Normal, full-term newborn infants or healthy premature infants may have decreased levels of protein C activity (15% to 50%), which may not reach adult levels until later in childhood or early adolescence.
Discontinue Coumadin therapy 1 month prior to testing. Heparin greater than 1.0 U/mL, coumadin, and fibrinolytic agents interfere with this assay. Coumadin decreases Protein C.
Methodology: Clot-based on prolongation of APTT assay.
High doses of standard heparin (greater than 1.0 U/mL) may interfere with a PT mixing study. Anti-Xa agents such as Rivaroxaban may also interfere with PT mixing studies. Clinical correlation is advised.
Synonyms:
Protein C
PTC
Platelet Aggregations with ATP Release
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Turnaround Time:
1 day
Test Schedule:
Specimen must be collected at OHSU and by appointment only. Call Lab Client Services at 503-494-7383 to schedule. Appointments can be scheduled Tuesday and Thursday, 9:00 am to 12:00 pm, at least 1 hour apart and no more than 3 per day.
Specimen Requirements:
Four full 2.7 mL whole blood LIGHT BLUE top (3.2% sodium citrate) tubes AND one 3 mL whole blood LAVENDER top (EDTA) tube. Do NOT send in pneumatic tube system. Do NOT spin. Stability is 3 hours at room temperature.
Avoid aspirin for 10 days and non-steroidal anti-inflammatories for at least 2 days prior to test. Fasting samples are preferred as food interferences are possible.
Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.
OHSU clinics must cab specimen to the H&T Lab, Dillehunt Hall, Room 3050 if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-8445.
Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.
Pediatric Specimen Requirements:
Three full adult-sized 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate, AND one PEDIATRIC LAVENDER top tube. Do NOT send in pneumatic tube system. Do NOT spin. Stability is 3 hours at room temperature.
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Comments:
This test is to screen for specific hereditary and acquired platelet functional abnormalities such as rare congenital disorders (Glanzmann's thrombasthenia and Bernard-Soulier syndrome).
Synonyms:
Aggregation
Plt Agg
Lupus Inhibitor Evaluation with Reflexes
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Includes:
DRVV Confirm Normalized Ratio; SCT Confirm Normalized Ratio, if indicated: SCT Mix, DRVVT Mix.
To exclude anticoagulant effects, a reflex Heparin, Thrombin Time, and INR will be performed when the lupus panel screens or normalized ratios are prolonged. Additional Charges will apply.
Turnaround Time:
5 days
Test Schedule:
Tuesday and Thusday
Specimen Requirements:
Three full 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate. Specimens must be processed and frozen within 2 hours of specimen collection.
Send 3- 1.5ml aliquots of platelet poor plasma, samples must remain frozen during storage and shipment.
Stability is 14 days at -20 C.
Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.
Pediatric Specimen Requirements:
Three full pediatric 1.3 mL LIGHT BLUE top tubes, 3.2% sodium citrate. Specimens must be processed and frozen within 2 hours of specimen collection.
Send 2- 1.5ml aliquots of platelet poor plasma, samples must remain frozen during storage and shipment.
Stability is 14 days at -20 C.
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Reference Range:
dRVVConfirm Normalized Ratio: less than or equal to 1.20
SCT Confirm Normalized Ratio: less than or equal to 1.23
Comments:
Testing for lupus inhibitors is not recommended while a patient is on anticoagulation therapy because heparins, direct Xa inhibitors, warfarin, and direct thrombin inhibitors variably confound the parent test systems (SCT, dRVVT, and mixing studies).
The Lupus Inhibitor panel does not include serologic studies (anti-cardiolipin and anti-beta 2 glycoprotein 1) which are also useful in evaluating anti-phospholipid syndrome (APS). For comprehensive APS evaluation follow ISTH guidelines.
Synonyms:
Dilute Viper Venom Time (DVVT) with Reflex to DVV Confirm Ratio
Lupus Anticoagulant
Lupus Panel
Factor XI Activity
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Turnaround Time:
1 to 3 days
Test Schedule:
Monday through Friday 8:30 am to 4:30 pm. Call 503-494-8445 if STAT.
Units:
Critical Values:
Less than 5%.
Specimen Requirements:
Two full 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.
OHSU clinics must cab specimen to the Core Lab, Hatfield Research Center, 9th Floor (room 9D20) if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-7383.
Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.
For referral testing, submit one tube with 1.0 mL frozen platelet poor citrated plasma.
Pediatric Specimen Requirements:
One full pediatric 1.3 mL LIGHT BLUE top tube, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Reference Range:
65% to 150%
For children less than 6 months, see link to published reference ranges (Opens in a new window).
Comments:
Assay to document Factor XI deficiency. Homozygous patients have bleeding symptoms with post-trauma/post-surgical hemorrhage, epistaxis, hematuria, and menorrhagia. Excessive postpartum hemorrhage is especially common. Severity of bleeding does not always correlate with the plasma level of factor XI. This may relate in part to the mechanism of activation of factor XI. Heterozygotes are asymptomatic. Homozygotes have prolonged whole blood clotting time and APTT. Prothrombin time, thrombin time, bleeding time, platelet count, and platelet function tests are normal.
Avoid warfarin (Coumadin) therapy for 2 weeks and heparin therapy for 2 days prior to test.
Methodology: APTT based clotting method.
High doses of standard heparin (greater than 1.0 U/mL) may interfere with a PT mixing study. Anti-Xa agents such as Rivaroxaban may also interfere with PT mixing studies. Clinical correlation is advised.
Synonyms:
Factor 11
Factor 11A
Factor XI
FXIA
Factor X, Chromogenic Assay
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Turnaround Time:
1 to 3 days
Test Schedule:
Monday through Friday 8:30 am to 4:30 pm. Call 503-494-7383 if STAT.
Units:
Interpretation:
Oral anticoagulant therapeutic range: 20% to 40%.
Critical Values:
Less than 5%.
Specimen Requirements:
Two full 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.
OHSU clinics must cab specimen to the Core Lab, Hatfield Research Center, 9th Floor (room 9D20) if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-7383.
Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.
For referral testing, submit one tube with 1.0 mL frozen platelet poor citrated plasma.
Pediatric Specimen Requirements:
One full pediatric 1.3 mL LIGHT BLUE top tube, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Reference Range:
59% to 129%
For children less than 6 months, see link to published reference ranges (Opens in a new window).
Comments:
Diagnostic Criteria: Factor X, Chromogenic Assay is indicated to monitor oral anticoagulant therapy in patients with a lupus inhibitor or thrombin inhibitor (argatroban, etc.) + coumadin. This method is not affected by the lupus inhibitor or by therapeutic heparin levels.
Assay performed to document congenital and acquired factor deficiency. (Order Factor X, chromogenic if patient on argatroban, lepirudin or other thrombin inhibitors).
Acquired deficiencies occur with significant hepatic dysfunction and with oral anticoagulant (coumarin) therapy. Factor X levels are most frequently used to monitor oral anticoagulant therapy in patients with lupus inhibitors. Factor X deficiency may be associated with primary systemic amylodosis. The rare clinical condition (X deficiency) is inherited as autosomal, incompletely recessive. About 25 cases of hereditary factor X deficiency have been reported.
Methodology: Chromogenic
High doses of standard heparin (greater than 1.0 U/mL) may interfere with a PT mixing study. Anti-Xa agents such as Rivaroxaban may also interfere with PT mixing studies. Clinical correlation is advised.
Synonyms:
Activity
Chromogenic Factor 10
Chromogenic Factor X
Factor VII Activity
Orderable EAP code:
Billable EAP Codes:
CPT Codes:
Lab Section:
Turnaround Time:
1 to 3 days
Test Schedule:
Monday through Friday 8:30 am to 4:30 pm. Run weekly.
Units:
Critical Values:
Less than 5%
Specimen Requirements:
Two full 2.7 mL LIGHT BLUE top tubes, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.
• Tubes with rubber stopper: fill to line on label.
• Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
• Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
• Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.
OHSU clinics must cab specimen to the Core Lab, Hatfield Research Center, 9th Floor (room 9D20) if processing is delayed or not possible on site. A phone call is helpful to alert the lab at 503-494-7383.
Detailed specimen collection and processing instructions are located under Lab Sections and then the Hemostasis and Thrombosis (Opens in a new window) section.
For referral testing, submit one tube with 1.0 mL frozen platelet poor citrated plasma.
Pediatric Specimen Requirements:
One full pediatric 1.3 mL LIGHT BLUE top tube, 3.2% sodium citrate. Hemostasis & Thrombosis Lab sodium citrate specimens must be processed and frozen within 2 hours of specimen collection. Stability is 14 days at -70 C.
For pediatric patients requiring multiple coagulation tests, please call 503-494-7383 regarding draw volumes.
Reference Range:
50% to 129%
For children less than 6 months, see link to published reference ranges (Opens in a new window).
Comments:
Avoid warfarin (Coumadin) therapy for 2 weeks and heparin therapy for 2 days prior to the test.
Assay to document factor VII deficiency. Deficiency of factor VII should be considered in patients with a prolonged prothrombin time but a normal APTT. While isolated deficiency is rare, two forms exist. Both are autosomal recessive and affect both sexes. In one form the VII molecules are decreased while In the second group an abnormally formed molecule is produced. Bleeding symptoms may be severe in homozygotes and include epistaxis, ecchymoses, GI bleeding, hemarthroses, menorrhagia, and umbilical cord hemorrhage. Fatal cerebral hemorrhage may occur. Heterozygotes are usually asymptomatic. Homozygotes have prolonged prothrombin time (corrected by adding normal plasma) but normal APTT, cephalin activated clotting time, and thrombin time.
Methodology: PT based clotting method.
High doses of standard heparin (greater than 1.0 U/mL) may interfere with a PT mixing study. Anti-Xa agents such as Rivaroxaban may also interfere with PT mixing studies. Clinical correlation is advised.
Synonyms:
F7A
Factor 7
FVII A