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Orderable Name GNPLT Platelet Disorders, Comprehensive Gene Panel, Next-Generation Sequencing, Varies


Ordering Guidance


The test is designed to evaluate a variety of hereditary platelet disorders and to be utilized for genetic confirmation of a phenotypic diagnosis of a hereditary platelet disorder.

 

This test is not designed to evaluate for hereditary bleeding disorders. For patients with clinical suspicion of an inherited bleeding disorder, it is important to exclude plasmatic factor deficiencies e.g., von Willebrand disease, hemophilia, or other factor deficiencies prior to considering an inherited platelet function defect. If bleeding is the indication for testing and testing for hereditary bleeding disorders is desired, bleeding panels are available. See GNBLF / Bleeding Focused Gene Panel or GNBLC / Bleeding Comprehensive Panel.

 

For assessment of hereditary platelet disorders that have ultrastructural abnormalities, such as gray platelet syndrome, order PTEM / Platelet Transmission Electron Microscopic Study, Whole Blood.

 

For assessment of hereditary platelet disorders due to quantitative surface glycoprotein deficiencies, order PLAFL / Platelet Glycoprotein Flow Platelet Surface Glycoprotein by Flow Cytometry, Blood.

 

Customization of this panel and single gene analysis for any gene present on this panel are available. For more information see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies.

 

Targeted testing for familial variants (also called site-specific or known variants testing) is available for the genes on this panel. See FMTT / Familial Variant, Targeted Testing, Varies. To obtain more information about this testing option, call 800-533-1710.



Shipping Instructions


Specimen preferred to arrive within 96 hours of collection.



Necessary Information


Platelet Esoteric Testing Patient Information is required. Testing may proceed without the patient information; however, the information aids in providing a more thorough interpretation. Ordering providers are strongly encouraged to fill out the form and send with the specimen.



Specimen Required


Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.

 

Submit only 1 of the following specimens:

 

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient (preferred) 4 days/Refrigerated

 

Specimen Type: Skin biopsy

Supplies: Fibroblast Biopsy Transport Media (T115)

Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin.

Specimen Volume: 4-mm punch

Specimen Stability Information: Refrigerated (preferred)/Ambient

Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.

 

Specimen Type: Cultured fibroblasts

Container/Tube: T-25 flask

Specimen Volume: 2 Flasks

Collection Instructions: Submit confluent cultured fibroblast cells from a skin biopsy from another laboratory. Cultured cells from a prenatal specimen will not be accepted.

Specimen Stability Information: Ambient (preferred)/Refrigerated (<24 hours)

Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.


Forms

1. Platelet Esoteric Testing Patient Information is required.

2. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing (Spanish) (T826)

3. If not ordering electronically, complete, print, and send an Coagulation Test Request (T753) with the specimen.

Useful For

Evaluating hereditary platelet disorders in patients with a personal or family history suggestive of a hereditary platelet disorder

 

Diagnosing hereditary platelet disorders for patients in whom phenotypic testing is nondiagnostic, but there is a strong clinical suspicion of the hereditary platelet disorder

 

Confirming a hereditary platelet disorder diagnosis with the identification of a known or suspected disease-causing alteration in one or more of 70 genes associated with a variety of hereditary platelet disorders

 

Determining the disease-causing alterations within one or more of these 70 genes to delineate the underlying molecular defect in a patient with a laboratory diagnosis of a platelet disorder

 

Identifying the causative alteration for genetic counseling purposes

 

Prognosis and risk assessment based on the genotype-phenotype correlations

 

Providing a prognosis in syndromic hereditary platelet disorders

 

Carrier testing for close family members of an individual with a hereditary platelet disorder diagnosis

 

This test is not intended for prenatal diagnosis.

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CULFB Fibroblast Culture for Genetic Test Yes No

Testing Algorithm

The clinical workup for detecting inherited platelet disorders should begin with a careful review of the complete blood cell count and peripheral blood smear results as well as other platelet tests, such as light transmission platelet aggregometry electrical impedance whole blood aggregometry, platelet function analyzer 100 (PFA-100), platelet transmission electron microscopy (TEM) and platelet flow cytometric analysis. TEM is an essential tool for laboratory diagnosis of various hereditary platelet disorders that have ultrastructural abnormalities, such as gray platelet syndrome. Flow cytometry is the preferred method to assess hereditary platelet disorders due to quantitative surface glycoprotein deficiencies.

 

Platelet laboratory testing may not be able to identify all inherited platelet disorders. Occasionally, the clinical picture may be consistent with a defect in primary hemostasis, but the results of platelet function tests may be normal or non-diagnostic.

 

Genetic testing for hereditary platelet disorders is indicated if:

-Platelet tests indicate a deficiency or functional abnormality

-There is a clinical suspicion for a hereditary platelet disorder due to family history or patient’s clinical presentation

-Acquired causes of deficiencies associated with platelet disorders have been excluded

 

If a platelet disorder is a concern, a set of clinical guidelines from the British Society for Haematology on testing for heritable platelet disorders is freely available.(1)

 

For skin biopsy or cultured fibroblast specimens:

For skin biopsy or cultured fibroblast specimens, fibroblast culture testing will be performed at an additional charge. If viable cells are not obtained, the client will be notified.

Method Name

Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing

Specimen Type

Varies

Specimen Minimum Volume

Blood: 1 mL; Cultured fibroblasts/skin biopsy: see Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

An interpretive report will be provided.

Day(s) Performed

Varies

Report Available

28 to 42 days

CPT Code Information

81443

88233-Tissue culture, skin, solid tissue biopsy (if appropriate)

88240-Cryopreservation (if appropriate)