Test Catalog

Test ID: MBX    
Muscle Pathology Consultation

Useful For Suggests clinical disorders or settings where the test may be helpful

Obtaining a rapid, expert opinion on muscle biopsy specimens for neuromuscular disease

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

A battery of enzyme histochemical stains will be performed on frozen tissue; additional histochemical stains or immunostains may be performed on frozen tissue; other tests can be performed as indicated and will be charged separately. The reviewing neuromuscular pathologist will determine the need for additional testing.


For all consultations, ancillary testing necessary to determine a diagnosis is ordered at the discretion of the Mayo Clinic neuromuscular pathologist. An interpretation, which includes an evaluation of the specimen and determination of a diagnosis, will be provided within a formal pathology report.


Frozen tissue sent for consultation: Appropriate additional stains may be performed at an additional charge.


Slides sent for consultation: Special stains and studies performed on the case should be sent with the case for review. In order to determine an accurate diagnosis, some of these stains or studies may be deemed to warrant repeat testing at an additional charge at the discretion of the reviewing Mayo Clinic neuromuscular pathologist. The interpreting neuromuscular pathologist may also request frozen tissue to perform additional studies that may be considered necessary for diagnosis.


Note: Testing requested by the referring physician (immunostains, etc) may not be performed if deemed unnecessary by the reviewing Mayo neuromuscular pathologist. Electron microscopic studies are not performed on muscle biopsy specimens. For more information see Why Electron Microscopy is Not Performed on Muscle Biopsy Specimens in Special Instructions.


See Pathology Consultation Ordering Algorithm in Special Instructions.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

This consultative practice strives to bring the customer the highest quality of diagnostic neuromuscular pathology, aiming to utilize only those ancillary tests that support the diagnosis in a cost-effective manner, and to provide a rapid turnaround time for diagnostic results.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation Provides information to assist in interpretation of the test results

Results are reported in a formal neuromuscular pathology report that includes diagnosis and an interpretive comment, if necessary. The formal pathology report is faxed or sent by mail according to the preference of the referring institution.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Be aware that poor freezing and improper handling of the muscle tissue may hinder the neuromuscular pathologist's interpretation of the biopsy. It is crucial to provide a properly handled muscle specimen. In this regard, see directions for Muscle Biopsy Specimen Preparation sheet in Special Instructions. A shipping kit is available (T541) and is recommended for collecting and shipping muscle specimens. It includes a container for the tissue, collection instructions, the Muscle Histochemistry Information Sheet, and a box to ship the specimen.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Engel AG: The muscle biopsy. In: Engel AG, Franzini-Armstrong C eds. Myology. 3rd ed. McGraw-Hill 2004:681-690

2. Liewluck T, Sorenson EJ, Walkiewicz MA, Rumilla KM, Milone M: Autosomal dominant distal myopathy due to a novel ACTA1 mutation. Neuromuscul Disord. 2017 Aug;27(8):742-746

3. Engel AG, Redhage KR, Tester DJ, Ackerman MJ, Selcen D: Congenital myopathy associated with the triadin knockout syndrome. Neurology. 2017 Mar 21;88(12):1153-1156

4. Niu Z, Pontifex CS, Berini S, et al: Myopathy with SQSTM1 and TIA1 variants: Clinical and pathological features. Front neurol. 2018 Mar 19;9:147

5. Nicolau S, Liewluck T, Shen XM, Selcen D, Engel AG, Milone M: A homozygous mutation in GMPPB leads to centronuclear myopathy with combined pre- and postsynaptic defects of neuromuscular transmission. Neuromuscul Disord. 2019 Aug;29(8):614-617

6 Nicolau S, Liewluck T, Tracy JA, Laughlin RS, Milone M: Congenital myopathies in the adult neuromuscular clinic: Diagnostic challenges and pitfalls. Neurol Genet. 2019 Jun 4;5(4):e341

7. Liewluck T, Niu Z, Moore SA, Alsharabati M, Milone M: ACTA1-myopathy with prominent finger flexor weakness and rimmed vacuoles. Neuromuscul Disord. 2019 May;29(5):388-391

8. Nicolau S, Liewluck T, Elliott JL, Engel AG, Milone M: A novel heterozygous mutation in the C-terminal region of HSPB8 leads to limb-girdle rimmed vacuolar myopathy. Neuromuscul Disord. 2020 Mar;30(3):236-240

Special Instructions Library of PDFs including pertinent information and forms related to the test