OSAC 2021-N-0020 Best Practice Recommendation

for Limited Friction Ridge Examinations

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OSAC 2021-N-0020

Best Practice 

Recommendation for 

Limited Friction Ridge 

Examinations

Friction Ridge Subcommittee]

Physics and Pattern Interpretation Scientific Area Committee]

Organization of Scientific Area Committees (OSAC) for Forensic Science
OSAC 2021-N-0020 Best Practice Recommendation

for Limited Friction Ridge Examinations

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OSAC Proposed Standard

OSAC 2021-N-0020

Best Practice Recommendation for 

Limited Friction Ridge Examinations

Prepared by 

Friction Ridge Subcommittee

Version: 2.0

April 2022

Disclaimer:

This OSAC Proposed Standard was written by the Friction Ridge Subcommittee of the Organization of 

Scientific Area Committees (OSAC) for Forensic Science following a process that includes an open 

comment period. This Proposed Standard will be submitted to a standards developing organization and is 

subject to change.

There may be references in an OSAC Proposed Standard to other publications under development by 

OSAC. The information in the Proposed Standard, and underlying concepts and methodologies, may be 

used by the forensic-science community before the completion of such companion publications.

Any identification of commercial equipment, instruments, or materials in the Proposed Standard is not a 

recommendation or endorsement by the U.S. Government and does not imply that the equipment, 

instruments, or materials are necessarily the best available for the purpose.
OSAC 2021-N-0020 Best Practice Recommendation

for Limited Friction Ridge Examinations

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Table of Contents

1. Introduction ..................................................................................................................... 4

2. Scope ................................................................................................................................. 4

3. Terms and Definitions..................................................................................................... 4

4. General Recommendations............................................................................................. 5

5. Appendix A: Change Log................................................................................................ 7
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1. Introduction

1.1. This document has been developed with the objective of improving the efficiency while 

maintaining the quality and consistency of friction ridge examination practices.

1.2. For the purposes of this document, examinations include both latent print processing 

(conducted in a laboratory setting) and friction ridge examinations. These examinations 

and their results should be within the examination’s limitations and/or the probative 

needs of the customer, in consultation with the customer, and their results should be 

provided to customers in a timely manner. In some cases, limiting or deferring certain 

examinations provides more timely results to the customer and conserves the resources 

of the forensic service provider (FSP).

1.3. Limited examinations are exams that are not complete with regard to the FSP’s 

capabilities; evidence may exist that has not been partially or fully processed and/or 

latent prints exist that have not been analyzed and/or compared.

1.3.1. Limited examinations are not performed through random sampling.

1.4. In some situations, limited examinations are advantageous to FSPs and its customers for 

any of the following reasons (not an all-inclusive list):

1.4.1. probative value of the evidence

1.4.2. crime type considerations (i.e. people versus property)

1.4.3. backlog reduction

1.4.4. increased case throughput

1.4.5. effective resource allocation and usage

1.5. In this document, the following verbal forms are used: “shall” indicates a requirement, 

“should” indicates a recommendation; “may” indicates permission; and “can” indicates a 

possibility or capability. 

2. Scope

2.1. This document describes what limited examinations are and provides the best practice 

recommendations on how limited examinations should be conducted. It also describes 

what documentation is necessary if limited examinations are utilized by a forensic 

service provider.

2.2. This document does not address limiting the collection and preservation of evidence.

3. Terms and Definitions

For the purposes of this document, the following terms and definitions apply:

3.1. Customer: Client, authority, organization or person(s) requesting the forensic services.
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3.2. Examination: The act or process of observing, searching, detecting, recording, 

prioritizing, collecting, analyzing, measuring, comparing, and/or interpreting.

3.3. Examiner (Friction Ridge)/Competent Friction Ridge Examiner: An individual who has 

successfully completed their FSP’s training program and has demonstrated to the FSP 

that they possess the knowledge, skills and abilities to perform the tasks required of their 

current position. An individual authorized to conduct friction ridge examinations for the 

FSP by observing and interpreting data, making decisions, forming conclusions and

opinions, issuing reports and/or providing testimony.

3.4. Forensic Service Provider (FSP): A forensic science entity or forensic science 

practitioner providing forensic science services.

3.5. Friction Ridge Detail/Features: The combination of ridge flow, ridge characteristics, and 

ridge structure of friction ridge skin, as observed and reproduced in an impression. A 

large subset of the observed data used to compare and interpret similarity or dissimilarity 

between two impressions.

3.6. Limited processing: the selective application of sequential processing without exhausting 

the full capabilities of the FSP.

3.7. Minutia: The point where a friction ridge begins, terminates, or splits into two or more 

ridges. A subset of the friction ridge detail/features traditionally consisting of ridge 

endings, bifurcations, and dots/short ridges used to compare and interpret similarity and 

dissimilarity between two impressions.

3.8. Observed Data: Any demonstrable information observed within an impression that an 

examiner relies upon to reach a decision, conclusion or opinion. This has historically 

been expressed as “features” or “minutiae,” but the use of the broader term “observed 

data” is inclusive of other types of data that may be considered beyond minutiae, such as 

quality, scars, creases, edge shapes, pore structure, and other friction ridge features.

3.9. Sequential Processing: the application of chemical and/or physical friction ridge 

development techniques in a specific order to target specific constituents of friction ridge 

impressions which may be visualized for examination and to maximize the preservation 

of the friction ridge detail during each process. FSP policy and capabilities dictate the 

full spectrum of sequential processes available to examiners and a minimum standard for 

their application.

4. General Recommendations

4.1. Evidence Processing

4.1.1. The potential probative value of evidence should be assessed when deciding 

which evidence to process first (i.e. not processing items determined to be 
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for Limited Friction Ridge Examinations

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irrelevant to the case, halting comparisons after multiple identifications have been 

made to the same individual, etc.).

4.1.2. Offense type may be considered by the FSP or in consultation with the customer 

when determining which cases to process first. Offenses that present a more 

egregious threat to public safety may be prioritized; however, consideration 

should be given when determining the extent to which any particular case may be 

examined.

4.1.3. When considering backlog mitigation strategies, selecting specific processing 

techniques with higher sensitivity instead of conducting full sequential processing 

may be necessary to improve efficiency and throughput. When selecting limited 

processing techniques, the FSP should consider the potential of a given technique 

for negatively impacting subsequent processing. At a minimum, any friction 

ridge detail of potential value that has been developed shall be photographed 

and/or retained and the integrity of the item shall be maintained for potential 

future examination. Backlog reduction may also include conducting limited 

processing of certain items (e.g. cartridge cases) that have a low success rate.

4.1.4. FSP submission guidelines may include packaging recommendations that will 

maximize latent print processing results (i.e. separating drugs from the packaging 

prior to submission).

4.2. Friction Ridge Examinations

4.2.1. Examiners may search and/or compare friction ridge impressions developed on 

the most probative items first and may stop when the investigative needs of the 

customer have been met (i.e. person(s) of interest is/are identified). Additional 

comparisons can be completed by the request of the customer.

4.2.2. Develop and retain all suitable friction ridge impressions; however, defer any 

remaining manual comparisons once each named person of interest has been 

identified on the surface or item(s).

4.2.3. Submit and search all AFIS quality friction ridge impressions first and report any 

conclusions made from the automated searches. Non-AFIS quality friction ridge 

impression comparisons may be completed upon an additional request from the 

customer.

4.2.4. Perform automated searches using auto-extracted minutiae first (e.g. an imageonly search) and if no identifications are made, perform a second search by using 

manually-encoded minutiae or ‘cleaning up’ the auto-extracted minutiae.

4.2.5. FSP policy may allow or require the restriction on which databases are searched 

to reduce the amount of time spent on each examination (e.g. only search a local 

database for specific types of crimes).
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4.3. Necessary Documentation and Reporting

4.3.1. The FSP shall communicate with the customers when performing limited 

examinations; both to determine if the examination is still required and to 

establish the extent or order of the examinations.

4.3.2. Any FSP that performs or plans to perform limited examinations shall notify any 

customers of that policy in advance. The extent of the examination shall be 

documented in the case file and reported to the customer. This documentation 

shall include any evidence that was not processed and/or any friction ridge 

impressions that were of potential value that were not analyzed or compared.

4.3.3. Any limited examination approach used should be conducted minimizing the 

inhibition of future processing and/or comparisons. This would allow additional 

examinations at a later date. It is up to the FSP to weigh the advantages and 

disadvantages in deciding whether to implement a limited examination policy.

5. Appendix A: Change Log

Version Date Change

1.0 3/18/2021 Original Issue

2.0 4/5/2022 Final Issue