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Test ID: Factor XIII
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Factor XIII Assay
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Useful For
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To detect deficiency of Factor XIII. Monitoring of substitution therapy with Factor XIII concentrate
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Method name and description
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Chromogenic.
Test is performed using Sysmex CS5100 analyzer. FXIII in the sample is converted by the action of thrombin in to FXIIIa. Fibrin formed by thrombin also accelerates this reaction. Fibrin produced by the action of thrombin is prevented from forming clots by an aggregation inhibiting Peptide and held in solution.
FXIIIa cross-links a specific peptide substrate to glycine ethyl ester, thereby releasing ammonia. The ammonia released is then determined in a parallel enzymatic reaction.
The decrease in NADH is measured by monitoring the absorbance at 340 nm.
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Clinical information
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Factor XIII is responsible for stabilizing a fibrin clot. Factor XIII deficiency is an extremely rare autosomal recessive bleeding disorder. Homozygous individuals (FXIII <1%) experience soft tissue hemorrhage, hemarthrosis, and hematomas. Typically, as delayed bleeding start 24 to 48 hours after the initial hemostatic response to an injury. Heterozygous carriers may be asymptomatic; however, may cause recurrent spontaneous abortions in females.
Acquired factor XIII deficiency is rare, occurs as a result of development of autoantibodies and result in adult-onset bleeding.
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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 >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 c disorder. History of chronic diseases .
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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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For age > 18 years: : 70 – 140 %.
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.
* The reference range is quoted from literature. The reference range values have not been verified /established by lab.
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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 Years
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1 Years-5 Years
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5 Years-10 Years
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10 Years-18 Years
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27-131
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44-144
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63-152
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42-128
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71-139
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76-133
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64-133
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Factors affecting test performance and result interpretation
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No interference up to:
Triglycerides 149 mg/dL.
Hemoglobin 600 mg/dL 600.
Hemoglobin 600 mg/dL 600.
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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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