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Test Code EM Electron Microscopy, Varies

Reporting Name

Electron Microscopy

Useful For

Providing information to aid in the diagnosis of medical disorders such as storage diseases, CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), and primary ciliary dyskinesia

Method Name

Electron Microscopy

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

EM


Ordering Guidance


Tumor biopsies are only accepted as part of a pathology consultation, order PATHC / Pathology Consultation.

 

For nontumorous renal specimens, order RPCWT / Renal Pathology Consultation, Wet Tissue.

 

For platelet disorders, order PTEM / Platelet Transmission Electron Microscopic Study, Whole Blood.

 

For muscle specimens, order MBX / Muscle Pathology Consultation.

 

For CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) genetic testing, order NTC3Z / NOTCH3 Gene, Full Gene Analysis, Varies.

 

For cardiac specimens, order ANPAT / Anatomic Pathology Consultation, Wet Tissue.

 

For neuronal ceroid lipofuscinosis (NCL) testing, see NCLW / Neuronal Ceroid Lipofuscinosis, Two-Enzyme Panel, Leukocytes or NCLGP / Neuronal Ceroid Lipofuscinosis (Batten Disease) Gene Panel, Varies



Shipping Instructions


Whole blood specimens must arrive within 48 hours of collection.



Necessary Information


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

1. Completed Electron Microscopy Patient Information must be submitted with each specimen.

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



Specimen Required


Specimen Type: Fixed wet tissue

Supplies: Electron Microscopy Kit (T660)

Container/Tube: Electron Microscopy Kit 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. Do not place on ice, dry ice, or freeze.

Additional Information:

1. PATHC / Pathology Consultation may be added if deemed necessary by the reviewing pathologist.

2. Liver/gastrointestinal and hair shaft specimens are not acceptable. Testing will be canceled if one of these specimen types is received.

 

For neuronal ceroid lipofuscinosis (NCL) testing only

Specimen Type: Whole blood

Container/Tube: Green top (sodium heparin) or yellow top (ACD solution B)

Specimen Volume: 5 mL

Collection Instructions: Send whole blood specimen in original tube. Do not aliquot.

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


Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
EM Ambient (preferred)
  Refrigerated 

Reject Due To

Muscle tissue
Fat pads
Hair shaft
Liver/gastrointestinal tissue		 Reject

Reference Values

An interpretive report will be provided.

Day(s) Performed

Monday through Friday

CPT Code Information

88348

LOINC Code Information

Test ID Test Order Name Order LOINC Value
EM Electron Microscopy 34166-9

 

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

Secondary ID

70316

Clinical Information

Transmission electron microscopy is an important diagnostic tool used in the comprehensive assessment of human disease and is most often used in conjunction with other methods such as light microscopy and immunohistopathological techniques. This fundamental technology can provide both confirmatory and diagnostic value to the pathologist and clinician.

Interpretation

The images and case histories are correlated and interpreted by a pathologist who is an expert in the field of the suspected diagnoses.

 

Results will be provided by telephone. If requested, representative images showing diagnostic features will be sent.

Cautions

Certain factors are necessary for interpretation of electron microscopic images as follows:

-Optimal fixation of viable and representative tissue is imperative.

-The tissue submitted must have been viable at the time of fixation.

Clinical Reference

1. Jennette JC, D'Agati VD, eds. Heptinstall's Pathology of the Kidney. 7th ed. Wolters Kluwer; 2023

2. Shoemark A, Boon M, Brochhausen C, et al. International consensus guideline for reporting transmission electron microscopy results in the diagnosis of primary ciliary dyskinesia (BEAT PCD TEM Criteria). Eur Respir J. 2020;55(4):1900725. doi:10.1183/13993003.00725-2019

3. Schroder JA. Diagnostic transmission electron microscopy. Imaging and Microscopy. 2012. Accessed October 14, 2022. Available at www.imaging-git.com/science/electron-and-ion-microscopy/diagnostic-transmission-electron-microscopy

Method Description

The fixed tissues received are postfixed and stained in osmium tetroxide, dehydrated, and embedded in epoxy resin. Resin blocks are trimmed and semithin (1-micron) survey sections stained with toluidine blue are viewed using a light microscope. Blocks of interest are retrimmed, and the area for observation is then ultrathin sectioned, placed on copper mesh grids, and stained with lead citrate. The sections are examined with a transmission electron microscope operated at an appropriate kV. Images are digitally captured and stored electronically.(Winey M, Meehl JB, O'Toole ET, Giddings TH Jr. Conventional transmission electron microscopy. Mol Biol Cell. 2014;25(3):319-23. doi:10.1091/mbc.E12-12-0863)

Report Available

5 to 10 days

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

Specimen Retention Time

Residual tissue: 2 months

Highlights

For more information see Primary Ciliary Dyskinesia.