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Test Code Plt EM Platelet Transmission Electron Microscopic Study

Useful For

Diagnosing platelet disorders

Method Name

Platelet Ultra-structural Examination by Transmission Electron Microscopy

Reporting Name

Platelet TEM, B
Seattle Children's Hospital Note:

Clinical System Name: Platelet Electron Microscopy

Specimen Type

Whole Blood ACD

Specimen Required

Send specimen Monday through Wednesday.


Collection Container/Tube:

Preferred: Yellow top (ACD, solution B)

Acceptable: Yellow top (ACD, solution A)

Specimen Volume: 6 mL

Collection Instructions:

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

2. Do not transfer blood to other containers.

Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood ACD Ambient 72 hours

Reject Due To


Mild OK; Gross reject


Mild OK; Gross OK




Later than 96 hours from collection

Reference Values

Mean dense granules/platelet ≥1.2

Method Description

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)

Day(s) and Time(s) Performed

Monday through Friday; 7 a.m.-3 p.m.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

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 U.S. Food and Drug Administration.

CPT Code Information



LOINC Code Information

Test ID Test Order Name Order LOINC Value
PTEM Platelet TEM, B In Process


Result ID Test Result Name Result LOINC Value
CK109 Platelet TEM In Process
CK110 Interpretation In Process


1. Platelet Esoteric Testing Patient Information in Special Instructions

2. If not ordering electronically, complete, print, and send a Coagulation Test Request Form (T753) with the specimen (