Test Id : HEPTP
Heparin Anti-Xa, Plasma
Useful For
Suggests clinical disorders or settings where the test may be helpful
Measuring heparin concentration:
-In patients treated with low-molecular-weight heparin preparations
-In the presence of prolonged baseline activated partial thromboplastin time (APTT) (eg, lupus anticoagulant, "contact factor" deficiency, etc)
-When unfractionated heparin dose needed to achieve desired APTT prolongation is unexpectedly higher (>50%) than expected
This test is not useful for monitoring therapy with the heparinoid "danaparoid."
Method Name
A short description of the method used to perform the test
Chromogenic Method
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
Anti-10a
Anti-Xa
Fragmin (Dalteparin)
Heparin Anti-Xa Assay, Plasma
Lovenox (Enoxaparin)
Low-Molecular Weight Heparin Assay
Unfractionated Heparin Assay
Specimen Type
Describes the specimen type validated for testing
Plasma Na Cit
Ordering Guidance
To test for the presence of inhibitors directed against factor X (FX), order 10INE / Factor X Inhibitor Evaluation, Plasma.
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Specimen Type: Platelet-poor plasma
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. For complete instructions see Coagulation Guidelines for Specimen Handling and Processing.
2. Centrifuge, aliquot plasma, and centrifuge plasma again.
4. Aliquot plasma into a plastic vial leaving 0.25 mL in the bottom of centrifuged vial.
Additional Information: Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
0.5 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Na Cit | Frozen (preferred) | 14 days | |
| Ambient | 2 hours |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Measuring heparin concentration:
-In patients treated with low-molecular-weight heparin preparations
-In the presence of prolonged baseline activated partial thromboplastin time (APTT) (eg, lupus anticoagulant, "contact factor" deficiency, etc)
-When unfractionated heparin dose needed to achieve desired APTT prolongation is unexpectedly higher (>50%) than expected
This test is not useful for monitoring therapy with the heparinoid "danaparoid."
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Heparins are sulphated glycosaminoglycans that inactivate thrombin, factor Xa, and several other coagulation factors; act by enhancing activity of the plasma coagulation inhibitor, antithrombin III; and prolong the activated partial thromboplastin time (APTT). The anti-Xa assay is the preferred method for monitoring low-molecular-weight heparin (LMWH) therapy because of reduced sensitivity of APTT. Heparin is absent in normal plasma. The heparin level obtained must be analyzed in the context of the treatment given to the patient (type of heparin, dosage, administration mode, time of sampling, etc) and the desired therapeutic effect. It is clinically recommended that platelet counts be monitored frequently in patients receiving unfractionated heparin or LMWH in order to detect heparin-induced thrombocytopenia.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Adult Therapeutic Range
UFH therapeutic range: 0.30-0.70 IU/mL
(6 hours following initiation or dose adjustment)
LMWH therapeutic range: 0.50-1.00 IU/mL for twice daily dosing*
LMWH therapeutic range: 1.00-2.00 IU/mL for once daily dosing*
LMWH prophylactic range: 0.10-0.30 IU/mL
*Sample obtained 4 to 6 hours following subcutaneous injection
Interpretation
Provides information to assist in interpretation of the test results
Results above the therapeutic range may be supratherapeutic suggesting that the heparin dose may need to be decreased.
Results below the therapeutic range may be subtherapeutic suggesting that the heparin dose may need to be increased.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Plasma specimen must be depleted of platelets by repeat centrifugation before freezing.
In order to reduce the influence from heparin antagonists, such as platelet factor 4, dextran sulfate is included in the reaction mixture.
Very low endogenous antithrombin III (AT III) levels might result in spuriously-low results.
Antibodies to bovine factor X or AT III can interfere with assay (very rare).
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Marci CD, Prager D. A review of the clinical indications for the plasma heparin assay. Am J Clin Pathol. 1993;99(5):546-550
2. Houbouyan L, Boutiere B, Contant G, et al. Validation of analytical hemostasis systems: measurement of anti-Xa activity of low-molecular-weight-heparins. Clin Chem. 1996;42(8 Pt 1):1223-1230
3. Jeske W, Messmore HL Jr, Fareed J. Pharmacology of heparin and oral anticoagulants. In: Loscalzo J, Schafer AI. Thrombosis and Hemorrhage. 2nd ed. Williams and Wilkins; 1998:1193-1204
4. Monagle P, Michelson AD, Bovill E, Andrew M. Antithrombotic therapy in children. Chest. 2001;119(1 Suppl):344S-370S
5. Fraser G, McKenna J. Monitoring low molecular weight heparins with antiXa activity: house of cards or firm foundation? Hospital Pharmacy. 2003;38(3):202-211. doi:10.1177/001857870303800302
6. Nutescu EA, Spinler SA, Wittkowsky A, Dager WE. Low-molecular-weight heparins in renal impairment and obesity: available evidence and clinical practice recommendations across medical and surgical settings. Ann Pharmacother. 2009;43(6):1064-1083
7. Hoffman R, Benz Jr EJ, Silberstein LE, et al. Hematology: Basic Principles and Practice. 7th ed. Elsevier; 2018
Method Description
Describes how the test is performed and provides a method-specific reference
The Liquid Anti-Xa kit (ACL TOP) is a 1-stage chromogenic assay based on a synthetic chromogenic substrate and on factor Xa inactivation.(Package insert: HemosIL Liquid Anti-Xa. Instrument Laboratory; R5, 12/2020)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Sunday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
85520
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| HEPTP | Heparin Anti-Xa, P | 3274-8 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| HEPTP | Heparin Anti-Xa, P | 3274-8 |