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Test Code EM Electron Microscopy

Advisory Information

For nontumorous renal specimens, see RPCWT / Renal Pathology Consultation, Wet Tissue for Electron Microscopy.

For platelet disorders, see PTEM / Platelet Transmission Electron Microscopic Study.

For muscle specimens, see MBX / Muscle Pathology Consultation.

For CADASIL genetic mutation testing on blood, contact Mayo Clinic Laboratories.

For Cardiac Biopsy disorders, see ANPAT / Anatomic Pathology Consultation, Wet Tissue

Shipping Instructions

Whole blood specimens must arrive within 48 hours of draw.

Necessary Information

Failure to supply the following documentation will result in a testing delay:

1. A completed Electron Microscopy Patient Information Sheet must be submitted with each specimen.

(See Special Instructions for hyperlink)

2. Tissue source required and reason for electron microscopy must be indicated for testing to be performed.

3. Tumor biopsies must be accompanied by a history.

Specimen Required

Tumor biopsies must be accompanied by hematoxylin and eosin-stained slides and a paraffin block.


Supplies: Electron Microscopy Kit (T660)

Specimen Type: Fixed wet tissue

Container/Tube: Electron Microscopy Kit (T660) or leak-proof container

Specimen Volume: Entire specimen

Collection Instructions: Collect specimen according to the instructions in Electron Microscopy Procedures of Handling Specimens for Electron Microscopy in Special Instructions. Do not place on ice, dry ice, or freeze.

Additional Information: PATHC / Pathology Consultation may be added if deemed necessary by the reviewing pathologist.


Alternative Specimen Type: Whole Blood

Note: If test indication is for neuronal ceroid lipofuscinosis (NCL), whole blood may be submitted in lieu of fixed wet tissue. This is only applicable for a presumptive diagnosis of NCL; specimens submitted for any other reason will be rejected.

Container/Tube: Electron Microscopy Kit (T660), green top (sodium heparin), or yellow top (ACD [solution B])

Specimen Volume: 5 mL

Collection Instructions: Do not transfer blood to other containers.

Useful For

Identifying tumor


Diagnosing medical disorders such as storage diseases, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and primary ciliary dyskinesia

Method Name

Electron Microscopy

Reporting Name

Electron Microscopy

Specimen Type


Specimen Minimum Volume


Specimen Stability Information

Specimen Type Temperature Time
EM Ambient (preferred)

Reject Due To








Muscle tissue, Fat pads

Reference Values

An interpretive report will be provided.

Day(s) and Time(s) Performed

Monday through Friday; Varies

Analytic Time

4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test uses a standard method. Its performance characteristics were 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
EM Electron Microscopy In Process


Result ID Test Result Name Result LOINC Value
71033 Interpretation 59465-5
71034 Participated in the Interpretation No LOINC Needed
71035 Report electronically signed by 19139-5
71037 Material Received 81178-6
71788 Case Number 80398-1