Test Catalog

Test ID: PTEM    
Platelet Transmission Electron Microscopic Study, Whole Blood

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

This test identifies dense granule deficiency by semiquantitative counting of dense granules on whole mount grids by technologists and verified by a hematopathologist/hematologist.


Whole mount-transmission electron microscopy is a quick and simple way to examine platelet electron opaque or dense granule (DG) by laying platelet-rich plasma on an electron microscopy grid. The high content of calcium in DG blocks electron beam of TEM and creates a sharp dark shadow.(White JG: The dense bodies of human platelets: inherent electron opacity of the serotonin storage particles. Blood. 1969 Apr;33[4]:598-606; Winey M, Meehl JB, O'Toole ET, Giddings TH Jr: Conventional transmission electron microscopy. Mol Biol Cell. 2014 Feb;25[3]:319-323 doi: 10.1091/mbc.E12-12-0863)

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 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.

10 days

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

Not retained

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