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Test Code KI67B Ki-67(MIB-1), Breast, Quantitative Immunohistochemistry, Automated

Advisory Information

Ki-67 immunohistochemistry testing on intracystic papillary carcinoma and solid papillary carcinoma, without clearly stating invasive carcinoma, is not appropriate and will be canceled without processing.


If ordering for diagnostic purposes, order PATHC / Pathology Consultation and request the stain.

Shipping Instructions

Attach the green pathology address label included in the kit to the outside of the transport container.

Necessary Information

Include accompanying pathology report stating the final diagnosis. If not available, a preliminary diagnosis is acceptable only if it refers to invasive or metastatic breast carcinoma.


Pathologist's name, address, and phone number are required.

Specimen Required

Specimen Type:

Preferred: Formalin-fixed, paraffin-embedded tissue block containing invasive or metastatic breast carcinoma

Acceptable: 2 Unstained sections, containing invasive or metastatic breast carcinoma, on charged slides cut at 4 microns <1 month ago. Tissue on the slides should have been fixed in 10% neutral buffered formalin.

Supplies: Pathology Packaging Kit (T554)

Collection Instructions: Submit paraffin-embedded invasive or metastatic breast carcinoma tissue.

Additional Information: Paraffin block will be returned with the final report.


If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

Pathology Test Request Form (T246) (

Oncology Test Request Form (T729) (

Useful For

Determining proliferation of tumor cells in paraffin-embedded tissue blocks from patients diagnosed with breast carcinoma

Disease States

  • Breast cancer

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
KIBM Ki67 Breast IHC Manual No No

Testing Algorithm

Cases that are not able to be scanned for automated analysis will be changed to the manual process for analysis.

Method Name

Immunohistochemistry, Automated Quantitation

Reporting Name

Ki67 Breast IHC Automated

Specimen Type


Specimen Stability Information

Specimen Type Temperature Time
Special Ambient (preferred)

Reject Due To









Clinical Information

Ki-67 (MIB-1 clone) is a monoclonal antibody that reacts with cells undergoing DNA synthesis by binding to the Ki-67 antigen, a marker known to be expressed only in proliferating cells. By measuring the amount of tumor cells expressing Ki-67, an estimate of DNA synthesis can be determined. Studies suggest that Ki-67 (MIB-1) analysis of paraffin-embedded tissue specimens may provide useful prognostic information in various tumor types.

Reference Values

Varies by tumor type; values reported from 0% to 100%


Results will be reported as a percentage of tumor cells staining positive for Ki-67 (MIB-1). Quantitative Ki-67 (MIB-1) results should be interpreted within the clinical context for which the test was ordered.


The scoring method using the Aperio digital pathology system was developed and validated in the Molecular Anatomic Pathology Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic (see Method Description).


The paraffin block analyzed must be representative of the patient's tumor.


Test results should be interpreted in the context of clinical findings and other laboratory data.

Method Description

A 4 micron-thick section is cut from the paraffin block. The section is stained with an immunoperoxidase method using the monoclonal antibody Ki-67 (MIB-1 clone). This is the paraffin nuclear epitope to the Ki-67 antigen. Any nucleus that has an antigen-antibody complex will cause the bright-field, brown chromogen, diaminobenzidine (DAB), to precipitate onto it. All nuclei, both DAB positive and negative, are counterstained with diluted hematoxylin.


Ki-67 (MIB-1)-stained slides are scanned using the Aperio ScanScope instrument, which captures digital images of the patient slide. The technologist views the digitized image on a computer monitor and using a tracing tool available in ImageScope (Aperio Technologies Inc), traces around areas of invasive or metastatic cancer capturing no less than 75% of the total cancer within the image. The traced areas are then analyzed using an image analysis algorithm that renders the percentage of positive-staining tumor nuclei. The slides and test results are then reviewed by a pathologist who provides a final interpretation.(Unpublished Mayo method)

Day(s) and Time(s) Performed

Monday through Friday; 8 a.m.-5 p.m.

Analytic Time

2 days

Specimen Retention Time

Until 1 week after results are reported. Material made at Mayo Clinic may be retained at Mayo Clinic indefinitely.

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
KI67B Ki67 Breast IHC Automated In Process


Result ID Test Result Name Result LOINC Value
70995 Interpretation 50595-8
70996 Participated in the Interpretation No LOINC Needed
70997 Report electronically signed by 19139-5
70999 Material Received 81178-6
MA023 Tumor type 44638-5
MA024 Tumor classification In Process
71627 Disclaimer 62364-5
71841 Case Number 80398-1