Test Catalog

Test Id : PNP

Platelet Neutralization Procedure, Plasma

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aiding in the confirmation or exclusion of the presence of a lupus anticoagulant (LAC) inhibitor  when used in conjunction with other appropriate coagulation tests

 

Aids in differentiating deficiencies or inhibitors of specific coagulation factors (eg, factor VIII inhibitor) from LAC inhibitors

Method Name
A short description of the method used to perform the test

Only orderable as a reflex. For more information, see:

ALUPP / Lupus Anticoagulant Profile, Plasma

ALBLD / Bleeding Diathesis Profile, Limited, Plasma

AATHR / Thrombophilia Profile, Plasma and Whole Blood

APROL / Prolonged Clot Time Profile, Plasma

ADIC / Disseminated Intravascular Coagulation/Intravascular Coagulation and Fibrinolysis (DIC/ICF) Profile, Plasma

 

Optical Clot-Based

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Platelet Neutralization Procedure

Aliases
Lists additional common names for a test, as an aid in searching

Inhibitor, Lupus-Like

Lupus Anticoagulant

Lupus-Like Anticoagulant

Lupus-Like Inhibitor

Platelet Neutralization Procedure

Platelet Neutralization - (Off hours order CSHS)

Activated Partial Thromboplastin Time

PNP (Platelet Neutralization Procedure)

Specimen Type
Describes the specimen type validated for testing

Plasma Na Cit

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Only orderable as a reflex. For more information see:

ALUPP / Lupus Anticoagulant Profile, Plasma

ALBLD / Bleeding Diathesis Profile, Limited, Plasma

AATHR / Thrombophilia Profile, Plasma and Whole Blood

APROL / Prolonged Clot Time Profile, Plasma

ADIC / Disseminated Intravascular Coagulation/Intravascular Coagulation and Fibrinolysis (DIC/ICF) Profile, Plasma

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

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

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aiding in the confirmation or exclusion of the presence of a lupus anticoagulant (LAC) inhibitor  when used in conjunction with other appropriate coagulation tests

 

Aids in differentiating deficiencies or inhibitors of specific coagulation factors (eg, factor VIII inhibitor) from LAC inhibitors

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Prolonged clotting times may be due to a variety of factors including the presence of clotting factor deficiencies, factor inhibitors, and lupus anticoagulants (antiphospholipid antibodies).

 

When a prolonged activated partial thromboplastin time (APTT) demonstrates inhibition on mixing with normal plasma indicative of presence of an inhibitor, the platelet neutralization procedure (PNP) is useful in determining if this inhibition is due to presence of a lupus anticoagulant (LAC).

 

The PNP involves the addition of washed, freeze-thawed platelets or buffer to the patient's plasma. An APTT is done on both mixtures and the clotting times are compared. Additional phospholipid supplied by the PNP reagent can absorb LAC, thereby diagnostically shortening the APTT.

 

For performance and interpretation of the PNP, the baseline APTT should be significantly prolonged (preferably at least 3 to 5 seconds above the upper limit of the reference range), and APTT inhibition must be demonstrated or suggested by a mixing study with normal plasma (ie, 1:1 mix fails to shorten into the normal range).

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.

Only orderable as a reflex. For more information see:

ALUPP / Lupus Anticoagulant Profile, Plasma

ALBLD / Bleeding Diathesis Profile, Limited, Plasma

AATHR / Thrombophilia Profile, Plasma and Whole Blood

APROL / Prolonged Clot Time Profile, Plasma

ADIC / Disseminated Intravascular Coagulation/Intravascular Coagulation and Fibrinolysis (DIC/ICF) Profile, Plasma

 

An interpretive report will be provided.

Interpretation
Provides information to assist in interpretation of the test results

Interpretation of the results of the platelet neutralization procedure (PNP) test is complex and needs to be performed in the context of results of mixing study of the prolonged activated partial thromboplastin time (APTT), the APTT PNP and the buffer control APTT, as well as results of other coagulation tests (eg, prothrombin time and thrombin time as well as available clinical information).

 

Plasma containing lupus anticoagulant (LAC) will demonstrate significant shortening of the prolonged inhibited APTT with the addition of platelets (by at least 4-5 seconds), when compared to baseline APTT, and the buffer control APTT typically will be 4 to 5 seconds longer than the PNP APTT.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The presence of heparin will cause a false-positive platelet neutralization procedure (PNP). The distinction is usually not difficult because the presence of heparin can be detected by a prolonged thrombin time and normal reptilase time.

 

The presence of coagulation factor V inhibitors or deficiency may also produce a false-positive PNP result. This can be suspected if the prothrombin time (PT) is significantly prolonged and may merit additional testing.

 

The presence of other coagulopathies or interfering conditions (causing false-positive PNP interpretation) should be evaluated by results of other tests (PT, thrombin time [TT], and other assays if needed) and by available clinical information.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Brandt JT, Triplett DA, Alving B, Scharrer I: Criteria for the diagnosis of lupus anticoagulants: an update. Thromb Haemost 1995;74(5):1185-1190

2. Brandt JT, Barna LK, Triplett DA: Laboratory identification of lupus anticoagulants: results of the second international workshop for identification of lupus anticoagulants. Thromb Haemost 1995;74(6):1597-1603

3. Gastineau DA, Kazmier FJ, Nichols WL, Bowie EJ: Lupus anticoagulant: an analysis of the clinical and laboratory features of 219 cases. Am J Hematol 1985;19:265-275

4. Cardel LK, Fisher PK, Heit JA, et al: Detection of lupus anticoagulants and anticardiolipin antibodies: prevalence of positive test in 665 patients. Thromb Haemost 1993;69:1221

5. Laboratory Hematology Practice. Edited by K Kottke-Marchant. Wiley Blackwell Publishing. 2012

Method Description
Describes how the test is performed and provides a method-specific reference

The platelet neutralization procedure (PNP) assay is performed on the Instrumentation Laboratory ACL TOP. Two cuvette wells are tested: 1 containing patient plasma and buffer and the other containing patient plasma and PNP platelet reagent. The contents of each cuvette well are combined and incubated with an APTT reagent containing phospholipid, a negatively charged contact factor activator, and buffer. After a specified incubation time, calcium is added to trigger the coagulation process in the mixture. Subsequently, the time to clot formation is measured optically using a wavelength of 671 nm for each cuvette well.(Triplett DA, Brandt MC, Kaczor D, and Shaeffer J: Laboratory diagnosis of lupus inhibitor: A comparison of the tissue thromboplastin inhibitor procedure with a platelet neutralization procedure. Amer J Clin Pathol 1983:79(6):678-682; Nichols WL, Kottke-Marchant K , Ledford-Kraemer MR et al:  Chapter 39: Lupus Anticoagulants, Antiphospholipid Antibodies, and Antipholpholipid Syndrome. In Laboratory Hematology Practice. Edited by K Kottke-Marchant. Wiley Blackwell Publishing. 2012. pp 509-525)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

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 Friday

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.

Same day/1 to 4 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

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 Regional Manager. 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 was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

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
PNP Platelet Neutralization Procedure In Process
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.
PNPPL Platelet Neutralization Procedure 40647-0
PNPSA PNP Buffer Control 43308-6

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports