Skip to main content

Standardize Kidney Biopsy Reporting and Data Collection

eye iconAt a glance

Current policy

Procurement kidney biopsies are a tool that OPOs and transplant doctors use to assess a deceased organ donor’s kidney for organ damage and potential kidney function. Over the years, kidney biopsies have become more widely used, but the information that is reported on the biopsies varies throughout the country. Currently, OPTN policy does not specify what information is required to be reported on a kidney biopsy.

Supporting media


View presentation PDF link

Proposed changes

  • OPOs will report consistent kidney biopsy information on the Standardized Pathology Report
  • Fields will be added to DonorNet for OPOs to share the kidney biopsy information
  • Fields will also be added to the Deceased Donor Registration (DDR) form in TIEDI, to align biopsy data collection in UNet

Anticipated impact

  • What it's expected to do
    • Improve consistency in biopsy reporting
    • Improve reliability of kidney biopies
    • Increase kidney allocation efficiency

Terms to know

  • Biopsy: a tissue sample from the body, removed and examined under a microscope to diagnose for disease, determine organ rejection, or assess donated organs or tissues.
  • Pathology: the branch of medicine that deals with the laboratory examination of body tissue samples for diagnostic or forensic purposes.

Click here to search the OPTN glossary

eye iconComments

UC San Diego Health Center for Transplantation | 03/23/2022

CASD generally supports the concept of standardizing the data collection and reporting process for kidney biopsy results, however, as written this proposal does not address the persistent underlying issue of resource challenges in addition to a lack of standards to assess the results in the context of transplant suitability so we cannot support it. We would recommend that the Committee consider identifying and partnering with experts across the country to first develop such standards and perhaps issuing guidance to the community before creating policy that adds burden without evidence of benefit.

Anonymous | 03/23/2022

The OPO Committee thanks the Kidney Transplantation Committee for their efforts in developing this proposal. The OPO Committee supports standardization of kidney biopsy reporting and potential benefits to streamlining offer evaluation. One member noted that Fibrin Thrombi and Cortical Necrosis are important biopsy characteristics for transplant programs evaluating possible AKI kidneys. A member shared it can be difficult to get kidney biopsies performed for donors at rural hospitals. The member recommended including some kind of brief education with the standardized report, to encourage pathologists less accustomed to procurement biopsy. One member pointed out biopsy results can often be delayed, which can negatively impact allocation efficiency as programs choose to wait for biopsy results to provide final acceptance.

Anonymous | 03/23/2022

The Committee thanks the OTPN Kidney Committee for their work in developing the proposal Standardize Kidney Biopsy Reporting and Data Collection and the opportunity to provide feedback. The Committee supports this proposal and provides the following feedback: 1) The proposal should consider a field on the kidney biopsy reporting form to indicate whether the biopsy was adequate per the 2018 Banff classification of renal allograft pathology guidelines. 2) The proposal should consider the addition of a field to indicate whether the clinician performing the biopsy is a renal pathologist; this would give programs more information as to the accuracy of the biopsy, leading to greater standardization. 3) Finally, the proposal should consider whether the biopsy was paraffin embedded or a frozen section.

Anonymous | 03/23/2022

Sentiment: 3 strongly support, 8 support, 0 neutral/abstain, 1 oppose, 0 strongly oppose. Comments: An attendee asked if the Kidney Committee considered possible delays in allocation if local hospitals aren’t reading biopsies. A commenter recommended adding arterial hyalinization to the scorecard. Another attendee suggested information detailed on the pathology slide should be something a general pathologist should be able to discern.

WVU Medicine | 03/23/2022

We support work to standardize biopsy reports but only support the proposal if arteriolar hyalinosis is added to data collection field.

American Society of Transplantation | 03/22/2022

The American Society of Transplantation is supportive of the proposal in concept and offers the following comments for consideration: 1. In the proposed standardized Pathology Report Data Fields: -Time when the biopsy was performed should be reported and added as a data field here -Expertise of reading pathologist should be specified- general pathologist, nephropathologist or other 2. In the proposed Data Elements and Definitions, the Fibrin thrombi should be defined further as to which capillaries it is present at (arteriolar, peritubular?) 3. In the proposed Modifications to the DDR, a category for “other” should be added for those less frequent findings that would not fit into any already specified category but may be of importance to note. 4. Identification of nodular diabetic glomerulosclerosis is likely aspirational. Early diabetic mesangial changes are difficult to recognize on frozen section, and when advanced, are typically associated with advanced chronic kidney disease and will therefore be rarely seen in donor biopsies. Nevertheless, the committee supports the initial inclusion of this field, with the expectation that a review will be performed to evaluate the utility of this measurement if future revisions to this instrument are suggested. 5. There is a risk of poor interobserver agreement at the lower end of the proposed scoring scales for Interstitial Fibrosis and Tubular Atrophy (IFTA) and vascular disease. There is some confusion in the Banff classification over IFTA, as fibrosis and atrophy have different cutoffs: no interstitial fibrosis (ci0) is scored as

View attachment from American Society of Transplantation

Association of Organ Procurement Organizations | 03/22/2022

Association of Organ Procurement Organizations supports Standardize Kidney Biopsy Reporting and Data Collection.

View attachment from Association of Organ Procurement Organizations

National Kidney Foundation | 03/22/2022

The National Kidney Foundation appreciates the opportunity to comment on the OPTN proposal, "Standardize Kidney Biopsy Reporting and Data Collection."

View attachment from National Kidney Foundation

Anonymous | 03/22/2022

11 strongly support, 10 support, 1 neutral/abstain, 0 oppose, 1 strongly oppose - Members of the region support the proposal. A couple of members expressed an interest in requiring renal pathologists complete the biopsy, or pathology slides should be scanned and uploaded to a web-based server to be accessed by all transplant centers for review. Another member requested an additional field added for arteriolar hyalinosis. Often, non-renal pathologists will say that there is no vascular disease because a large vessel with intimal fibrosis is not identified. However, rereads of these biopsies will show significant arteriolar hyalinosis. This can result in delayed discard once a kidney reaches a center or need for reallocation late in the process. Non renal pathologists are less likely to comment on arteriolar hyalinosis, but it is a finding that is more common and affects outcomes in the recipients. Another member requested the data associated with kidney utilization providing this standardized set of data. Additionally, there needs to be an ‘N/A’ option for some of the categories, if pathologist cannot determine from the frozen section provided the required information. Also, by providing data in this standard way, candidates should be listed by programs with their biopsy result criteria as filters in order to increase efficiency in kidney allocation and provide accountability at the transplant program acceptance practice. Requiring this policy without any transplant center accountability of what they are prepared to do with the information is counter-productive.

Anonymous | 03/21/2022

Sentiment: 6 strongly support, 6 support, 1 neutral/abstain, 0 oppose, 0 strongly oppose. Comments: Overall the region supported the proposal. An attendee commented that while standardizing the data is a step forward, but they would strongly recommend the committee consider incorporating diabetic changes into this proposal.

NATCO | 03/21/2022

NATCO supports the proposal “Standardize Kidney Biopsy Reporting and Data Collection” as a step toward increasing allocation efficiency, and agree that it will reduce inconsistency through more reliable reporting methods.

Anonymous | 03/21/2022

Sentiment: 3 strongly support, 13 support, 0 neutral/abstain, 0 oppose, 0 strongly oppose. Comments: Members of the region support the proposal. A member stated that the standardized data collection could much improve the proposal, "Establish Minimum Kidney Donor Criteria to Require Biopsy.” This proposal if implemented, in time, could clearly answer the question if there should be boundaries concerning when a program must or should not perform a kidney biopsy. This data is needed to ensure the community is maximizing kidney access. Another member noted that there needs to be continued work to standardize the reading of biopsies and tissue preparation. Additionally, the community should work towards having digital slides that can be reviewed, which would allow local pathologists to easily re-read biopsies. It was also noted that this would be a great opportunity for an ad hoc committee to put together a white paper on best practices for biopsy techniques, tissue prep, path interpretation, E-path, etc. Lastly, another member voiced concerns that there are some partner/donor hospitals with no pathology support to read these biopsies which could add more time to the already lengthy allocation process.

Anonymous | 03/18/2022

Sentiment: 5 Strongly Support; 7 Support; 0 Neutral/Abstain; 0 Oppose; 0 Strongly Oppose. Comments: Overall the region supported the proposal. One member asked that biopsies also be shared digitally. An attendee remarked that one of one of the challenges is that there is large variability in reporting across different pathologists and the only way to make this more systematic would be if slides could be scanned and reporting would be done by a selected group of pathologists in the country. Several members voiced support for the idea of central pathology. One individual commented their institution supports the criteria overall, but brought up a couple of suggestions. First, that it would be great to recommend to pathologist a minimum number glomeruli, and second, that the form needs a place to collect whether the donor was on dialysis or not. The individual also added that whole slide scanning would be helpful as well. A member expressed support for the proposal overall, but expressed concern in including fibrin thrombi in the reporting, due to the difficulty in visualizing fibrin thrombi in a frozen section. Another attendee suggested adding arterial hyalinosis, as it is an important factor in allocation and acceptance.

Amanda Bailey | 03/18/2022

Strongly support the proposed biopsy reporting that has been shown. I think OPO's may have issues obtaining biopsies as some hospitals do not have a pathologist available to read. I think another spin off for an item is to develop a universal electronic biopsy system where the biopsy can be read by a trained transplant nephrologist.

Anonymous | 03/17/2022

Sentiment: 3 strongly support, 8 support, 0 neutral/abstain, 0 oppose, 0 strongly oppose. Comments: Some members expressed concern about the discrepancies in biopsy readings based on the experience of the pathologist at the donor hospital. One added that unreliable reporting can be detrimental when accepting kidneys, resulting in unnecessary discards or transplanting less optimal kidneys. They went on to comment that quality control of pre-transplant biopsies by OPO’s is critical in the evaluation of kidney grafts, and should be required by policy. Another member commented that there are private services and platforms that improve the consistency of biopsy readings.

American Society of Transplant Surgeons | 03/17/2022

American Society of Transplant Surgeons supports.

View attachment from American Society of Transplant Surgeons

Gift of Life Donor Program | 03/17/2022

Gift of Life Donor Program thanks the Kidney Committee for their work in putting this policy proposal together and support efforts geared toward standard reporting and information sharing. We believe data associated with kidney utilization and this standardized set of data should be provided for review prior to implementation. “Not Applicable” should be available for: Nodular Mesangial Glomerulosclerosis, Interstitial Fibrosis and Tubular Atrophy (IFTA), Vascular Disease, Cortical Necrosis and Fibrin Thrombi in the event the pathologist is unable to determine those data elements from a frozen section. If this data will now be provided in a standard way, candidates should be listed by centers with their biopsy result criteria as filters to increase efficiency in kidney allocation and accountability at the transplant center. Requiring this policy without any transplant center accountability of what they are prepared to do with the information is counterproductive. Required implementation date must consider the impact this change will have on OPOs using electronic medical records. This change will have more than a nominal fiscal impact, will require updates to the electronic systems as well as a staff training component.

Anonymous | 03/16/2022

The Transplant Coordinators Committee thanks the OPTN Kidney Transplantation Committee for their proposal Standardize Kidney Biopsy Reporting and Data Collection. The Committee supports this proposal and the overall effort to improve standardization surrounding kidney biopsies. The Committee suggests that a guidance document for pathologists on biopsy reading best practices could be useful to assist in standardization.

Anonymous | 03/11/2022

The Operations and Safety Committee thanks the OPTN Kidney Transplantation Committee for their efforts on the Standardize Kidney Reporting and Data Collection proposal. The Committee supports this proposal. The Committee suggests to include a recommendation at the top of the form to specify an acceptable number of glomeruli (e.g. 50 glomeruli) per kidney in order to receive an adequate sample size. The Committee also suggests that the form be customizable to input OPO specific contact information. The Committee recommends adding renal replacement therapy data collection to this proposal. The Committee suggests establishing a pathway to notify accepting transplant programs that biopsy information is available. The Committee expresses concern regarding how to operationalize this proposal, as well as concern over the requirement when considering more remote transplant programs.

Anonymous | 03/02/2022

• Sentiment: 4 strongly support, 12 support, 1 neutral/abstain, 1 oppose, 0 strongly oppose • Comments: An attendee observed biopsy results are used in many circumstances as a reason to decline a kidney. The same attendee noted European transplant centers rarely request biopsies, and instead will transplant a kidney if it pumps. European centers have better utilization.

Anonymous | 02/23/2022

6 strongly support, 9 support, 0 neutral/abstain, 3 oppose, 0 strongly oppose - Region 8 generally supported this proposal with some opposition. Several members supported standardization of data reporting and collection. A member had a question regarding the “equal to or greater than 60 years” as a stand-alone criteria for biopsy, without including evaluation of other factors that are used for other age groups. A member pointed out that it may be too late to establish policy on the standard of care for donor kidney biopsies. The member explained that there is new FDA-approved equipment that images living (non-fixed) tissue and uses artificial intelligence to provide read assistance. The member suggested that these new technologic advances should be addressed and included in any standardization. A member explained that not every pathologist is willing to read these biopsy specifications and that it could create issues at the donor hospital. The member pointed out that there is an increase in donor activity at smaller hospitals. An OPO member commented that this is a “nice to have” template but that not all hospital pathologists are comfortable providing this data. It was stated that this proposal creates a burden, but a worthy burden.

Anonymous | 02/18/2022

0 strongly support, 21 support, 1 neutral/abstain, 1 oppose, 2 strongly oppose - Region 4 generally supported this proposal with one attendee commenting that biopsies should be read by reputable renal pathologists and pictures of the biopsies made available in UNET to the transplant centers. Another attendee commented that OPOs don’t have the ability to mandate a donor hospital pathologist do anything. They went on to express concerns that the full responsibility to comply with this policy is on the OPOs who don’t have the ability to enforce compliance. They added that a more reasonable approach would be to recommend using this tool and then broaden the availability and use of digital pathology and digital sharing of slides.

Anonymous | 02/16/2022

9 Strongly Support, 17 Support, 2 Neutral/Abstain, 4 Oppose, 0 Strongly Oppose - A member supported the standardization and suggested that it might be improved with virtual review of pathology slides by a certified kidney pathologist. Another member offered their support with the suggestion that the proposal needs further work to operationalize it, especially if a pathologist is unwilling to complete all required documentation. A member pointed out that there is no discussion in the proposal of the technological and other resource burden that implementation of this large and complex project will place on the OPTN. Further, there is no discussion of how this project fits in with the Kidney Committee's current work on Continuous Distribution. The member asked if this is this the right timing for implementation of this proposal? Or is there benefit to focusing on Continuous Distribution first, in terms of overall burden on the OPTN, OPOs, and transplant centers? A member suggested to add whether the kidney biopsy should be read by a general versus nephropathologist to the biopsy report.

Anonymous | 02/16/2022

4 Strongly Support, 8 Support, 2 Neutral/Abstain, 1 Oppose, 0 Strongly Oppose - Members in the region support the proposal, but offered feedback for the committee to consider. One member suggested that there also needs to be a consistent guideline for minimally acceptable sample, such as number of glomeruli. Another member suggested that an additional category be added to the standardized form that describes how the biopsy was prepared, either frozen or paraffin. Another member noted that there may be benefit to having a centralized location for reading biopsies to further enhance the goal of standardization. Another member added an important aspect to address in terms of standardization would be the pathologists read the biopsies and the quality of the biopsy specimen. If the pathologists do not have expertise with interpreting kidney biopsies or if the quality of the fixing of the specimen is not optimal (as most frozen section fixation are), the OPTN will get uninformative data. Lastly, a member suggested that the committee should next address is standardization of pumping criteria, i.e. pump all KDPI>85% or all DCD kidneys. This has the potential to increase the placement of "difficult to place" kidneys.

maxwell smith | 02/11/2022

1. Add a section for “number of arteries with elastic lamina” as the number of arteries seen is a good indicator of the quality of the biopsy 2. Do not include “Nodular Mesangial Glomerulosclerosis” as a specific section. All glomerular disease, if recognized, should be included in the “other comments” section 3. Add a section for “hyaline arteriolosclerosis” with none, mild, moderate, severe as per Banff Guidelines 4. Include a “not applicable” option for reporting of vascular disease for the cases in which no larger artery is sampled

Roslyn Mannon | 02/10/2022

I support this with caveats. As noted by my pathology colleague, some of the requested elements are not obtainable using frozen tissue. Based on my observations, the on call surgical pathologist reading of a frozen section misaligns frequently with the FFPE section stained for light microscopy (and often read by the pathologist experienced in evaluating kidney tissue). Will there be consistency in tissue preparation? Requirements of who reads the biopsy obtained? Will there be consideration for central biopsy reads as there are scanning tools available that don't require physical tissue or slides to be transported by mail/courier. Is this schema for the data collection based on some prior validated data set? But I completely understand the frustration of how donor biopsy is not informing the community adequately in making decisions that are consistently impactful in terms of recipient outcomes. Here is a recent commentary on some additional issues. Ref: PMID: 34045315

Parmjeet Randhawa | 02/09/2022

Arteriolar disease should be separated from Arterial disease. Hypertension and diabetes mellitus affect arterioles to a much greater degree. Minor arteriolar changes are hard to see on frozen, but that does not matter since severe disease can be recognized. Teaching how to recognize severe arteriolar disease on frozen sections should be a part of the future mission. Diabetic Kimmelstein nodules have been rightfully included even though early nodules are not recognized on frozen sections. Arteriolar change should be included as a separate item for the same reason.

Gift of Life Michigan | 02/04/2022

While we understand the occasional usefulness of biopsies in assessment of kidneys for transplantation, we believe there is a reliance upon imperfect biopsy reporting in determining suitability. The challenges of obtaining samples, and more importantly, having them read by an expert in the context of transplant suitability, renders the tests moderately informative at best. We believe the current OPTN guideline for kidney biopsies for donors with a KDPI greater than 85 or at transplant center request covers virtually every variable in the proposed list, and eliminates the need to mandate biopsies for some or all of the proposed criteria. We see no evidence that prescribing more biopsies will lead to any improvement to the current guidelines, and will impose still more obstacles for OPOs to efficiently manage organ donation.

Anonymous | 02/03/2022

I agree with the importance of standardizing biopsy reports, but I am a little concerned about the reliability of the readings. One problem with pre-implant biopsies is the limitation with frozen sections, but another problem is who reads them. It is well known that there is interobserver variability in the reading of kidney biopsies. Often there are large discrepancies in reading between a nephropathologist and a community pathologist who are not familiar with reading kidney (especially frozen) biopsies. Providing unreliable data can be confusing and sometimes even harmful to physicians and surgeons who accept organ offers. Performing biopsies is known to be associated with the renal graft discard. Although it may be a significant burden on OPOs, quality control of pre-transplant biopsies is critical in the evaluation of kidney grafts, and there should be a policy to ensure it. For example, each OPO could ensure the quality of kidney biopsy interpretation by demonstrating a contract with a nephropathologist or by showing the capacity to upload pathology images on a whole-slide scanner - it is not sufficient to use a cell phone camera to capture microscopic images.

Hans Gritsch | 02/03/2022

There should be an exception if the biopsy result will delay organ allocation significantly.

Anonymous | 02/03/2022

I applaud the kidney committee for their efforts regarding this proposal. I support the proposal but have concerns regarding the age criteria of ?60, which I think would lead to too many kidney biopsies and increase the likelihood of kidney discard. A 60-year-old with meeting no other criteria could have a KDPI as low as around 56%, which does not seem to indicate the need for a biopsy. KDPI alone should be used as a proxy for age. As written, I support the other criteria but propose the ag ?60 be removed.

Anonymous | 01/27/2022

proposal will help ensure that recipients do not receive sub-standard aka lousy kidneys as has happened far too many times resulting in graft rejection