Analytic Validation of Immunohistochemical Assays: A Comparison of Laboratory Practices Before and After Introduction of an Evidence-Based Guideline

Fitzgibbons, Patrick L.; Goldsmith, Jeffrey D.; Souers, Rhona J.; Fatheree, Lisa A.; Volmar, Keith E.; Stuart, Lauren N.; Nowak, Jan A.; Astles, J. Rex; Nakhleh, Raouf E.

doi:10.5858/arpa.2016-0558-cp

Cited by 20 publications

(32 citation statements)

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“…Information regarding changes in laboratory policies since 2010 is discussed in the companion article. 3 This article describes issues covered in the 2015 survey that were not addressed in the earlier survey. 2 Nearly 96% of laboratories documented validation procedures and 85% had written policies, 60% have separate written procedures for predictive and nonpredictive assays with 54.2% specifically addressing unmodified FDA-approved assays.…”

Section: Discussionmentioning

confidence: 99%

“…As the IHC validation LPG was developed, gaps were identified in the literature when data were not available to describe current IHC validation practices; this included the issue of what circumstances required assay revalidation. Analysis of the survey results led to a before and after comparison of laboratory practices, which is addressed in a companion paper by Fitzgibbons et al, 3 as well as new benchmark data from current laboratory practices that are described in this article. This article covers 3 broad aspects of IHC validation: laboratory policies on initial assay validation; revalidation practices; and the laboratory's actual practice during its most recent validation.…”

Section: Also See P 1247mentioning

confidence: 99%

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Analytic Validation of Immunohistochemistry Assays: New Benchmark Data From a Survey of 1085 Laboratories

Stuart¹,

Volmar²,

Nowak³

et al. 2017

Archives of Pathology &Amp; Laboratory Medicine

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Section: Discussionmentioning

confidence: 99%

Section: Also See P 1247mentioning

confidence: 99%

Analytic Validation of Immunohistochemistry Assays: New Benchmark Data From a Survey of 1085 Laboratories

Stuart¹,

Volmar²,

Nowak³

et al. 2017

Archives of Pathology &Amp; Laboratory Medicine

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“…Regarding awareness of the IHC VAL LPG, two-thirds of survey respondents (691 of 1057) reported that they were aware of the recommendations before receiving the questionnaire, with most of the remaining laboratories planning to review them within the next 6 months. 9 Telephone interviewees also reported awareness of its content. All interviewees suggested that the CAP should continue to make full efforts to keep awareness high, stating that current channels of notification and word of mouth are important.…”

Section: Resultsmentioning

confidence: 99%

“…These results included 1539 of 3064 surveys (50%) from laboratories participating in the CAP PT programs and 85 of 448 surveys (19%) from the nonparticipant laboratories. The quantitative IHC VAL survey results were tabulated, analyzed for comparison, and published separately by Fitzgibbons et al 9 In addition, Stuart et al 10 were able to publish new immunohistochemical validation benchmark data for laboratories.…”

Section: Al Guidelinementioning

confidence: 99%

Evaluating the Adoption of Laboratory Practice Guidelines

Goldsmith

Fitzgibbons

Fatheree

et al. 2019

Archives of Pathology &Amp; Laboratory Medicine

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Context.— To date, the College of American Pathologists (CAP) has developed 17 laboratory practice guidelines (LPGs) including updates. In 2013, the CAP was awarded a 5-year cooperative agreement grant from the United States Centers for Disease Control and Prevention to increase the effectiveness of LPGs. Objective.— To assess the awareness and adoption of 2 CAP LPGs: immunohistochemical (IHC) assay validation and initial workup of acute leukemia. Design.— Baseline surveys for each LPG were conducted in 2010 and 2015, respectively. To measure the adoption of guideline recommendations and inform future updates, a follow-up study consisting of surveys, telephone interviews, and focus group sessions was conducted in laboratories that indicated they perform IHC testing. A follow-up study for the acute leukemia LPG is planned. Results.— For the IHC Validation LPG, a total of 1624 survey responses, 40 telephone interviews, and discussions with 5 focus group participants were analyzed. The response rate for the aforementioned 3 modalities was 46%, 13%, and 3%, respectively. All modalities indicated most respondents were aware of the LPG and had adopted most or all of its recommendations. Respondents expressed needs for continued communication, increased specificity, and more prescriptive recommendations when the guideline is updated. Conclusions.— While data-driven development of evidence-based LPGs requires significant resources, active data collection to identify gaps and assess adoption contributes to improved laboratory testing practices in support of patient care. The CAP identified sustainable modalities to track metrics and developed multiple tools that should improve guideline development, adoption, and implementation. Of these modalities, written or electronic surveys were the most logistically feasible and had the highest response rate.

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“…With a smaller sample size, such as 5 positive specimens and 5 negative specimens, the 90% concordance benchmark is reached with only 1 discordant result, with a 95% confidence interval for the concordance estimate of 57% to 100% . Obtaining a sufficient number of samples for testing can prove challenging and may explain why, as of 2015, only half of laboratories surveyed had specific validation procedures in place for cytological materials . Validation specimens can be prepared from residual material from patient samples after a diagnosis has been established and reported.…”

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confidence: 99%

Immunohistochemical validation studies in effusion cytology: A cautionary tale

Pillappa

Kraft

2019

Cancer Cytopathology

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Precision medicine is driving the increased reliance of biomarker testing by immunohistochemistry (IHC) on cytological specimens. Although the original focus of IHC was to identify a target protein or analyte and deliver nominal results as a positive or negative signal, 1 it has now been expanded to include ordinal results in the form of scoring scales (eg, human epidermal growth factor receptor 2 [HER2] in breast cancer) or predefined positivity cutoffs (eg, a programmed death ligand 1 [PD-L1] assay). 2 The concept of validation as "demonstrating clinically relevant sensitivity and specificity" becomes even more important as IHC performed on limited samples takes on relevant roles not only for diagnosis but also for prognostic and therapeutic decisions. 3 Cell block preparations are the preferred type of cytological specimen for IHC of effusion fluids. In the United States, more than 10 methods are used for cell block preparation, the most common being plasma-thrombin, HistoGel (Richard-Allen Scientific, Kalamazoo, Michigan), and Cellient (Hologic, Marlborough, Massachusetts) 4 ; the first two use formalin, and the last one uses alcohol-based fixation and a unique processing method. Other cell block methods include simple sedimentation, collodion bags, and gelatin embedding. In an effort to boost cellular yields, variations of established methods have also been developed that include an alcohol pretreatment step before fixation in formalin. 5 IHC assays are typically validated with formalin-fixed, paraffin-embedded tissues. Laboratories need to determine whether cell blocks prepared with different fixation and/or processing protocols have equivalent immunoreactivity. 6 Multiple reports have documented decreased signal intensity or false-negative staining on alcohol-fixed cell blocks. Even the utilization of formalin postfixation has been reportedly plagued by decreased immunoreactivity. In a recent study of IHC on Cellient cell blocks, one-half of the antibodies tested failed the initial validation on IHC protocols optimized for formalin-fixed, paraffinembedded samples. 7 Alcohol fixation may also be introduced through the common practice of adding equal amounts of ethanol to effusion fluids at the time of collection. Fluids should ideally be received fresh by the laboratory and can be kept up to 14 days if refrigerated at 4°C with good preservation of morphology and immunogenicity. 8 One of the initial steps in the validation of IHC in cytological samples should be to test a limited selection of commonly used markers such as keratins, CD45, S100, and thyroid transcription factor (TTF1) in a set of cytological specimens to assess the influence of processing steps and specimen types on the assay results. A correlation with expected results in routinely processed tissue should be performed. 6

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Analytic Validation of Immunohistochemical Assays: A Comparison of Laboratory Practices Before and After Introduction of an Evidence-Based Guideline

Abstract: - Dissemination of the 2014 evidence-based guideline validation practices had a positive impact on laboratory performance; some or all of the recommendations have been adopted by nearly 80% of respondents.

Cited by 20 publications

References 10 publications

Analytic Validation of Immunohistochemistry Assays: New Benchmark Data From a Survey of 1085 Laboratories

Analytic Validation of Immunohistochemistry Assays: New Benchmark Data From a Survey of 1085 Laboratories

Evaluating the Adoption of Laboratory Practice Guidelines

Immunohistochemical validation studies in effusion cytology: A cautionary tale

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