26457 Platelet Transmission Electron Microscopic Study, Whole Blood (PTEM)

Diagnosing platelet disorders.

Genetics Test Information:

This test is indicated for assessing platelet ultra-structural abnormalities in congenital and acquired platelet disorders.

Patient Preparation: Fasting is preferred but not required.

Send specimen Monday through Wednesday.  Send specimen in original tube.  Do not transfer blood to other containers.

Specimens must be received in testing laboratory within 72 hours of collection.

Ship specimen overnight in an Ambient Shipping Box-Critical Specimens Only (T668) following the instructions in the mailer.

Necessary Information:

Platelet Esoteric Testing Patient 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.

Gross hemolysis

Gross lipemia

​Yellow top (ACD) whole blood specimens must be stored and transported at ambient temperature to be received within 72 hours of collection. Suboptimal transportation may cause falsely low dense granule counts.

Patients with either hereditary or acquired platelet disorders usually have bleeding diathesis, which can potentially be life threatening. A reliable laboratory diagnosis of a platelet disorder can significantly impact patients' and, potentially, their family members' clinical management and outcome.

Platelet (P) transmission electron microscopy (TEM) has been an essential tool for laboratory diagnosis of various hereditary platelet disorders since it was first used to visualize fibrin-platelet clot formation in 1955. PTEM employs 2 main methods to visualize platelet ultrastructure, whole mount (WM) TEM and thin section (TS) TEM.

WM-TEM is considered the gold standard test for diagnosing dense granule deficiencies in Hermansky-Pudlak syndrome, alpha-delta platelet storage pool deficiency, Paris-Trousseau-Jacobsen syndrome, Wiskott-Aldrich syndrome, TAR (thrombocytopenia, absent radii) syndrome, Chediak-Higashi syndrome, and more.

TS-TEM is a preferred method to visualize platelet alpha granules, other organelles, and abnormal inclusions.

Platelet disorders that can be detected by PTEM include (but are not limited to):

Delta granules (dense bodies):

-Hermansky Pudlak syndrome

-Wiskott-Aldrich syndrome

-Chediak Higashi syndrome

-Jacobson/Paris-Trousseau syndrome

-York platelet syndrome

-Storage pool deficiency, not otherwise specified

Alpha granules:

-Gray platelet syndrome

-White platelet syndrome

-X-linked GATA-1 variant

-Jacobson/Paris-Trousseau syndrome

 Alpha and delta granules:

-Alpha-delta storage pool deficiency

Ultrastructural abnormalities identified by platelet transmission electron microscopy (TEM) are evaluated by a Mayo hematopathologist.

Platelet size, alpha granules, Golgi complex, and abnormal inclusions will be assessed as part of the morphologic examination under TEM.

Distinct and sometimes pathognomonic ultrastructural abnormalities are found in Hermansky Pudlak syndrome, gray platelet syndrome with virtually absent alpha granules, white platelet syndrome, Medich giant platelet disorder, X-linked GATA-1 macrothrombocytopenia, and, recently described, York platelet syndrome.