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Test ID: Factor VIII, Factor IX, Factor XI and Factor XII
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Factor VIII assay, Factor IX assay, Factor XI assay and Factor XII assay
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Useful For
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The determination of coagulation factors VIII, IX, XI and XII in plasma is indicated in the following cases:
Diagnosing congenital or acquired factor deficiency states.
Clarifying the cause of a prolonged activated partial thromboplastin time(APTT).
Diagnosing von Willebrand disease when measured with von Willebrand factor (VWF antigen and VWF activity.
Determination of the activity of coagulation factors VIII and IX is employed for monitoring substitution therapy with Factor VIII or Factor IX concentrates in hemophilia A or B.
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Method name and description
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Turbidimetric
Test is performed using Sysmex CS5100 analyzer. Plasma deficient in any of the coagulation factors comprising the intrinsic pathway will result in a prolonged APTT. Coagulation factor deficient plasma can be used to confirm a factor deficiency in general, and to identify and quantify coagulation factor deficiency in patient plasma. A mixture of the factor deficient plasma and the patient plasma is tested in the activated partial thromboplastin assay and the result is interpreted using reference curve obtained with dilutions of calibration plasma mixed with deficient plasma. Patient plasma deficient in a specific factor will not be able to overcome the absence of the factor in the corresponding factor deficient plasma and therefore produce a prolonged partial thromboplastin assay time.
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Reporting name
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Factor VIII.
Factor IX.
Factor XI.
Factor XII.
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Clinical information
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Factor VIII, Factor IX, Factor XI and Factor XII are synthesized in the liver.
Factor deficiency is often discovered when activated partial thromboplastin time is found to be prolonged. The deficiency may cause a bleeding disorder.
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Specimen type / Specimen volume / Specimen container
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Plasma Na Cit. Platelet-poor plasma.
Specimen Volume:2.7 ml.
Container/Tube: Light-blue top (citrate)
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Collection instructions / Special Precautions / Timing of collection
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- Samples collected in HMC facilities MUST reach the coagulation laboratory within 1 hour of collection.
- Samples collected in non-HMC facilities / external clients: MUST reach coagulation laboratory within 1 hour of collection, if not applicable, centrifuge the whole blood and carefully remove the plasma (by pipette not by decanting) and send it in a temperature-controlled environment (18- 25 ºC) within 2 hours of centrifugation. If the transportation of the plasma can’t be within a maximum of 2 hours, prepare platelet-poor plasma as follows:
- Re-centrifuge the plasma again.
- Remove the top portion of plasma leaving approximately 250 ul in the bottom to discard.
- The double-centrifuged plasma should be aliquoted into labeled plastic tubes.
- Freeze immediately at -20 ºC or below
- Specimens must arrive frozen.
- If patient HCT is >55%, test will not be processed. The ordering Physician will be contacted to reorder the test and call the patient to go to Phlebotomy for recollection. Instruct the patient to inform the phlebotomy about his high HCT% , the phlebotomy will contact the lab to request a coagulation tube after adjusting amount of anticoagulant.
Note:
Collection of blood for coagulation testing through intravenous lines that have been previously flushed with heparin should be avoided, if possible. If the blood must be drawn through an indwelling catheter, possible heparin contamination and specimen dilution must be considered. When obtaining specimens from indwelling lines that may contain heparin, the line should be flushed with 5 mL of saline, and the first 5 mL of blood or 6-times the line volume (dead space volume of the catheter) be drawn off and not used for coagulation testing. For those specimens collected from a normal saline lock (capped off venous port) twice the dead space volume of the catheter and extension set should be discarded.
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Relevant clinical information to be provided
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Patient/family history of bleeding disorder. History of anticoagulant therapy.
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Storage and transport instructions
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Specimen Rejection Criteria
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Specimens with no label or missing required identification
Broken, leaking or contaminated specimen
Clotted samples
Under-filled or overfilled sample tubes.
Wrong sample container sample received
Improper specimen transport temperature (e.g. like specimens which are needed to be sent on ice)
Old specimen (test-dependent)
Grossly Hemolyzed sample (test-dependent)
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Biological reference intervals and clinical decision values
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Reference range: for age > 18 years
| Factor |
Reference Range |
| FVIII |
(70 -150 %) |
| FIX |
(70 - 120 %) |
| FXI |
(70 - 120 %) |
| FXII |
(70 - 150 %) |
For age ≤18 years:
Reference Interval: Factor levels are expressed as percent of blood plasma concentration.
By definition, pooled plasma contains 100 %( 1unit/ml) of each factor.
For Pediatric population up to 18 years old, the reference range is quoted from literature.
The reference range values have not been verified / established by lab.
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Factor
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0 Minutes-4 Days
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4 Days-1 Months
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1 Months-6 Months
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6 Months-1 Year
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1 Year-5 Years
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5 Years-10 Years
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10 Years-18 Years
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FVIII
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50-178
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50-154
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67-141
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70-213
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83-170
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75-163
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80-166
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FIX
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15-91
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15-91
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44-78
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46-114
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63-97
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60-108
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72-116
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FXI
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Oct-66
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23-87
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57-105
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64-129
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74-134
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78-131
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78-122
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FXII
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13-93
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11-83
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28-116
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31-126
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36-122
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37-123
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43-122
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Factors affecting test performance and result interpretation
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No interference up to:
Triglycerides 3028 mg/dL.
Hemoglobin 200 mg/dL.
Bilirubin 48 mg/dL.
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Turnaround time / Days and times test performed / Specimen retention time
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For routine ordered test : 3 working days
For stat ordered test :
- During the Laboratory working hours from 0700 hours to 1500 hours (Sunday to Thursday): TAT is Within 8hrs.
- After duty hours, weekends and on holidays: TAT is within 12 hrs. with the following requirements:
- Laboratory should be notified by telephone about the sending of a STAT sample.
- The sample should be hand-delivered to the central processing area and requesting them to deliver it immediately to the hematology coagulation lab.
Test is done : Daily.
Specimen retention time: NA
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