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PT and APTT : 1003609
MessageThe plasma aliquot must remain frozen. Freeze thaw cycle will adversely affect specimen integrity. CRITICAL FROZEN: Separate specimens must be submitted when multiple tests are ordered.
Test Code
PTAPTT or 1003609
Alias/See Also
APTT; Partial Thromboplastin Time, Activated; PTT; INR; Prothrombin Time, Plasma; Protime; PT
CPT Codes
85730, 85610
Instructions
Blue top tube, 3.2% sodium citrate.
• Obtain venous blood by clean venipuncture. Avoid slow-flowing draws and/or traumatic venipunctures as either of these may result in an activated or clotted specimen. Do not use needles smaller than 23 gauge. Do not leave the tourniquet on for an extended length of time before drawing the sample.
• A pilot tube (non-additive or light blue tube) before drawing coagulation specimens in light blue vacuum tubes is only necessary when using a butterfly blood collection set as this will cause reduced draw volume in the first tube. Discard the pilot tube.
• Fill light blue tubes as far as vacuum will allow and mix by gentle inversion. Exact ratio of nine parts blood to one part anticoagulant must be maintained. Inadequate filling of the sample tube will alter this ratio and may lead to inaccurate results. Patients who have hematocrit values above 55 percent should have the anticoagulant adjusted to maintain the 9:1 ratio. Use the following formula to determine the amount of anticoagulant to use: [(100 – Hct) / (595 – Hct) ]* total volume = amount of anticoagulant required.
• After collecting the blood, examine the tube to ensure that it is filled to within 90% of the fill line.
• Note: Specimens containing heparin should not be used for coagulation studies. If possible, stop heparin therapy before the draw to avoid contamination. Heparin interferes with most clotting assays. If heparinized line must be used to obtain the sample, flush line with 5mL saline and discard the first 5 mL of blood drawn into a syringe, or 6 “dead space” volumes of the line.
• Obtain venous blood by clean venipuncture. Avoid slow-flowing draws and/or traumatic venipunctures as either of these may result in an activated or clotted specimen. Do not use needles smaller than 23 gauge. Do not leave the tourniquet on for an extended length of time before drawing the sample.
• A pilot tube (non-additive or light blue tube) before drawing coagulation specimens in light blue vacuum tubes is only necessary when using a butterfly blood collection set as this will cause reduced draw volume in the first tube. Discard the pilot tube.
• Fill light blue tubes as far as vacuum will allow and mix by gentle inversion. Exact ratio of nine parts blood to one part anticoagulant must be maintained. Inadequate filling of the sample tube will alter this ratio and may lead to inaccurate results. Patients who have hematocrit values above 55 percent should have the anticoagulant adjusted to maintain the 9:1 ratio. Use the following formula to determine the amount of anticoagulant to use: [(100 – Hct) / (595 – Hct) ]* total volume = amount of anticoagulant required.
• After collecting the blood, examine the tube to ensure that it is filled to within 90% of the fill line.
• Note: Specimens containing heparin should not be used for coagulation studies. If possible, stop heparin therapy before the draw to avoid contamination. Heparin interferes with most clotting assays. If heparinized line must be used to obtain the sample, flush line with 5mL saline and discard the first 5 mL of blood drawn into a syringe, or 6 “dead space” volumes of the line.
Transport Container
Ambient Whole Blood: The blue top tube must be kept at room temperature. Do not refrigerate or freeze. If the specimen will not be tested in the laboratory within 24 hours of collection, then the tube must be centrifuged and plasma must be submitted frozen per instructions below.
Frozen Plasma: Centrifuge the blue top tube at a rate of speed to yield platelet poor plasma (<10,000 /uL), immediately remove only the top two-thirds of the platelet-poor plasma from the specimen using a plastic-transfer pipet (use of glass-transfer pipets may result in activation and/or clotting of the plasma) and transfer citrated plasma (Min. 0.5 mL) into a standard transport tube, and freeze the aliquot.
Frozen Plasma: Centrifuge the blue top tube at a rate of speed to yield platelet poor plasma (<10,000 /uL), immediately remove only the top two-thirds of the platelet-poor plasma from the specimen using a plastic-transfer pipet (use of glass-transfer pipets may result in activation and/or clotting of the plasma) and transfer citrated plasma (Min. 0.5 mL) into a standard transport tube, and freeze the aliquot.
Transport Temperature
Whole blood: Ambient.
Plasma: Frozen.
Plasma: Frozen.
Specimen Stability
Whole blood: Ambient: 24 hours
Plasma after separation from cells: Ambient: 4 hours; Refrigerated: 4 hours; Frozen: 2 weeks
Plasma after separation from cells: Ambient: 4 hours; Refrigerated: 4 hours; Frozen: 2 weeks
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Tubes not filled within 90% of the fill line will be rejected by the lab.
Methodology
Clotting
Setup Schedule
Sunday - Saturday
Report Available
1 day
Limitations
This test has not been validated for monitoring unfractionated heparin therapy. For testing that is validated for this type of therapy, please refer to Heparin, Anti-Xa, Unfractionated Assay (test code XAUNF or 1001022).
Reference Range
APTT:
0 to <4 days: Not established
≥4 days to <7 months: 24.0 – 37.0 seconds
≥7 months to <18 years: 24.0 – 34.0 seconds
≥ 18 years old: 22.0 – 32.0 seconds
This test has not been validated for monitoring unfractionated heparin therapy. For testing that is validated for this type of therapy, please refer to Heparin, Anti-Xa, Unfractionated Assay.
Prothrombin Time:
0 to <4 days: 10.2-15.4 seconds
≥ 4 days to <7 months: 9.9-13.6 seconds
≥ 7 months to <18 years: 9.7-12.3 seconds
≥ 18 years: 9.0-12.0 seconds
Coumarin Anticoagulant Therapeutic Ranges (INR):
2.0-3.0 Prophylaxis and Treatment of Venous Thromboembolism
2.5-3.5 Prevention of Recurrent Thromboembolism or treatment for Prosthetic Heart Valves
0 to <4 days: Not established
≥4 days to <7 months: 24.0 – 37.0 seconds
≥7 months to <18 years: 24.0 – 34.0 seconds
≥ 18 years old: 22.0 – 32.0 seconds
This test has not been validated for monitoring unfractionated heparin therapy. For testing that is validated for this type of therapy, please refer to Heparin, Anti-Xa, Unfractionated Assay.
Prothrombin Time:
0 to <4 days: 10.2-15.4 seconds
≥ 4 days to <7 months: 9.9-13.6 seconds
≥ 7 months to <18 years: 9.7-12.3 seconds
≥ 18 years: 9.0-12.0 seconds
Coumarin Anticoagulant Therapeutic Ranges (INR):
2.0-3.0 Prophylaxis and Treatment of Venous Thromboembolism
2.5-3.5 Prevention of Recurrent Thromboembolism or treatment for Prosthetic Heart Valves
Performing Laboratory
med fusion
