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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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1- Sample collected in HMC facilities/others and transported to the lab within 1hour :
• Collect sample into light blue-top (sodium citrate).
• Tubes must be filled to within +/- 10% of their proper volume, to provide a 9:1 ratio of blood to citrate.
2- Samples collected in HMC facilities / others and which are expected not to reach the lab within 1hour:
• Centrifuge the whole blood and carefully remove the plasma by pipette not by decanting and send the plasma in a temperature-controlled environment (18-25ºC ) within one hour of centrifugation.
• If the transportation of the plasma can’t be within a maximum of 2hour , prepare platelet-poor plasma as follow:
A: Re-centrifuge plasma again.
B: Remove the top portion of plasma leaving approximately 250 mcL in the bottom to discard.
C: The double-centrifuged plasma should be aliquoted (0.5 to 1 mL per aliquot) into labeled plastic tubes. The number of tests ordered will determine the aliquots needed.
D: Freeze immediately at -20 ºC or below .
E: Specimens must arrive frozen.
3- Sample for Platelets function studies (Platelets function assay) , Citrated whole blood should reach HMC within a maximum of 1-2 hours of collection.
4- For heparin monitoring, follow the above mentioned steps.
5- Consider patient HCT %. , if HCT is >55%, the volume of anticoagulant in the tube must be adjusted by the referring lab, as per the below table shows the volume of citrate (µL) to be removed from common sizes of coagulation specimen tubes prior to specimen collection. After removal of the specified volume of citrate, enough blood is added to fill the tube to the ideal volume.
| Hematocrit % |
Volume to be removed, µL |
| 2.7 ml Tube |
1.0 ml Tube |
| 56 |
50 |
20 |
| 57 |
50 |
20 |
| 58 |
60 |
20 |
| 59 |
60 |
20 |
| 60 |
70 |
30 |
| 61 |
70 |
30 |
| 62 |
80 |
30 |
| 63 |
80 |
30 |
| 64 |
90 |
30 |
| 65 |
90 |
30 |
| 66 |
100 |
40 |
| 67 |
100 |
40 |
| 68 |
110 |
40 |
| 69 |
110 |
40 |
| 70 |
120 |
40 |
| 71 |
120 |
40 |
| 72 |
130 |
50 |
| 73 |
130 |
50 |
| 74 |
140 |
50 |
| 75 |
140 |
50 |
| 76 |
150 |
50 |
| 77 |
150 |
60 |
| 78 |
160 |
60 |
| 79 |
160 |
60 |
| 80 |
170 |
60 |
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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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