Rapid Detection of Uropathogens and Antibiotic-resistant Genes Using Open Array Multiplex PCR Technology

Introduction/Objective

Introduction: Standard diagnostic practices for Urinary Tract Infection (UTI) take 2–3 days for pathogen identification and antibiotic susceptibility testing leading to delayed diagnosis and an increase in healthcare expenditures. The rapid diagnostics tool is highly desirable to identify the pathogen and its antibiotic-resistant genes directly from the samples. Our objective is to validate and evaluate the performance of Open array multiplex PCR for pathogen identification and antibiotic resistance genes.

Methods/Case Report

Method: Open array multiplex PCR method for 20 UTI pathogens was validated using ATCC organisms and inter-laboratory correlation using 50 urine samples. Briefly, samples were homogenized using Omni bead ruptor 96, and DNA was extracted using Hamilton Vantage. Customized open array and UTI chips with 20 most common urinary tract pathogen target and 13 resistant genes target specifically for UTI treatment were filled with Taqman open array PCR master mix and extracted DNA in a 1:1 ratio. UTI chips were prepared on Accufill and real-time PCR was performed on Quantstudio 12K flex. A total of 116 de-identified patient samples were analyzed.

Results (if a Case Study enter NA)

Result: The sensitivity, specificity, and accuracy of this method were more than 90% considering the reference method as the standard method. A total of 14 different types of organisms were detected. Escherichia coli (n=49) was the highest among all. Multiple pathogens were identified in 27 urine samples. Organisms such as Ureaplasma and Megasphaera 1 were detected in nine and four samples, respectively. All positive samples were resistant to at least one or two resistant genes. tetM and tetS were resistant among 72 samples, erm A, B, and C in 60 samples, ESBL in 30 and fosfo A in 21 samples.

Conclusion

Conclusion: The open array multiplex PCR technology may help in the early diagnosis and treatment that can improve patient care, shorten hospitalization, and reduces the economic burden.

Clinical Lab Decision Support System for Quality Test Ordering and Utilization with Increase Reimbursement

Introduction/Objective

It is estimated that at least 20% of the 5 billion lab orders submitted annually are inappropriate. Use of an appropriate laboratory test utilization management system (TUMS) can significantly overcome this. Laboratory Decision System (LDS) is the only automated TUMS to assist providers understand, select, order, and optimally utilize tests for disease diagnosis and management. This algorithm-based LDS rates and scores potential tests for any given disease and assigns an interpretable numeric score based on clinical relevance, medical necessity, and indication. Importantly, every orders using LDS will also have right CPT and ICD-10 codes assigned to meet the medical necessity and improve reimbursement. Therefore, in this study, we evaluated the performance of LDS as a testing utilization management system and its ability to improve the reimbursement.

Methods/Case Report

A total of 96,170 lab orders were analyzed from a reference laboratory. Of these, 814 tests were accompanied by an invalid ICD10 code and 44,671 tests or were accompanied by ICD10 that are described by Medicare as “never covered” because of inability to meet medical necessity. A total of 160,449 tests were subject to an Medicare policy review from which 112,400 tests met coverage criteria and 48,049 tests did not. These orders were then reevaluated using LDS, which can be accessed from app.medicaldatabase.com/site/api/cpoe or interfaced with EMR to determine if the system would have improved test selection and reimbursement.

Results (if a Case Study enter NA)

Of the original test order sample, 91.5% had an associated LDS score. Of these scored tests, 47.80% met coverage and 43.73% failed to meet coverage, according to the LDS Ranking System. Importantly, LDS provided recommendations for alternative diagnostic ICD10 codes or tests which could have aided physicians in choosing a more appropriate test or submitting a different ICD10 diagnostic code to meet medical necessity. 96.4% with an alternative ICD10 code or test with a score above 5, meeting medical necessity. 80.5% were recommended by the LDS system which would meet Medicare policies.

Conclusion

Use of such algorithm-based testing selection and ordering database that rates and scores potential tests for any given disease based on clinical relevance, medical necessity, and testing indication, would eventually help providers to select and order right test and reduce miss-utilization of tests.

Abstract P2-03-03: A multicenter clinical study of Xpert® breast cancer STRAT4 demonstrates high concordance with central lab ER, PgR, HER2, and Ki67 IHC and HER2 FISH tests in FFPE breast tumor tissues

The Xpert® Breast Cancer STRAT4 (STRAT4) is a CE-IVD marked, semi-quantitative, cartridge-based RT-qPCR assay for the detection of ESR1, PGR, ERBB2 (HER2), and MKi67 mRNAs from formalin fixed, paraffin embedded (FFPE) breast tumors. The assay is fast (< 2 hrs), reproducible, robust, and easy to perform.

The aim of this multicenter clinical study was to assess the performance characteristics of the STRAT4 assay relative to central lab immunohistochemistry (IHC) for ER, PgR, HER2, and Ki67 and to fluorescence in situ hybridization (FISH) for HER2 gene amplification.

Methods: A total of 200 archived primary invasive breast cancer FFPE blocks were sourced from Indivumed for this study. From each block, twelve (12) adjacent tissue sections (4-µm thickness) on slides were prepared for pathological H&E confirmation to define tumor area, and for testing by STRAT4, IHC (ER, PgR, HER2,Ki67), and HER2 FISH. Standard STRAT4 lysate preparation using a single unstained slide per specimen and testing on N=84, N=68, and N=48 samples was performed at 3 independent sites, respectively (2 US and 1 EU). A single slide from each specimen was also processed using the recommended concentrated lysate procedure for STRAT4 testing at Cepheid. All IHC and FISH testing was performed by a central academic reference laboratory in the US. For a given sample, STRAT4 data generated using the standard lysate procedure was included for concordance analysis when all target gene test results were valid. In cases where the standard lysate preparation yielded indeterminate test results for any target, data from the concentrated lysate preparation was used for the data analysis. Receiver Operating Characteristic (ROC) analysis, overall percent agreement (OPA), positive percent agreement (PPA), and negative percent agreement (NPA) between STRAT4 and IHC (IHC/FISH for HER2) were determined for ESR1,PGR, ERBB2, and MKi67.

Results: Of the 200 samples tested by STRAT4, all samples generated valid results for ESR1 and ERBB2, 199 of 200 samples were valid for PGR, and 198 of 200 samples were valid for MKi67 using the standard or concentrated lysate preparation protocol. One sample failed to generate results for both ER and PgR IHC. Twelve samples failed to yield HER2 FISH results.

The STRAT4 success rate and results concordance with IHC were comparable across study sites. OPA between STRAT4 and IHC was 97% for ESR1, 88.9% for PGR, 93.3% for HER2 (92.4% for IHC and FISH), and 90.7% for MKi67 (excluding IHC 10-20% staining). Areas under the ROC curves were 0.9922 for ESR1, 0.9509 for PGR, 0.9958 for ERBB2, and 0.9395 for MKi67.

Conclusion: STRAT4 measurements for ESR1, PGR, ERBB2 and MKi67 mRNA expression are robust and highly concordant with IHC (IHC/FISH for HER2). The technical portion of the assay is easily performed in < 2 hrs including hands-on time using standard FFPE tissue sections. Xpert STRAT4 offers local pathology labs an alternative to centralized, subjective IHC/FISH tests that require a higher level of expertise. Further investigations correlating STRAT4 markers directly with clinical outcomes in independent cohorts are in progress.

Citation Format: Wu NC, Wong E, Acca B, Birkmeier J, Tran L, Zhao S, Wong W, Chu VC, Ho K, Malek M, Lu C, Ge G, David K, Quigley NB, Beqaj SS, Davenport S, Weidler J, Bates M, Press M. A multicenter clinical study of Xpert® breast cancer STRAT4 demonstrates high concordance with central lab ER, PgR, HER2, and Ki67 IHC and HER2 FISH tests in FFPE breast tumor tissues [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-03-03.