Academic Appointments

  • Instructor, Pathology

All Publications

  • An up-conversion fluorescence lateral-flow immunoassay for rapid detection of Daratumumab in serum protein electrophoresis clinical samples. Clinica chimica acta; international journal of clinical chemistry Liu, Y., Tao, Y., Yeung, P. S., Lu, M., Liu, J., Yu, F., Shi, R., Yiqi Luo, R. 2024: 119677


    BACKGROUND: Daratumumab (DARA) is a commonly used monoclonal antibody (mAb) drug for the treatment of multiple myeloma (MM). Its appearance as a visible abnormal band in the gamma-region of a serum protein electrophoresis (SPEP) gel may interfere with the SPEP result interpretation. With the advantages of portability and rapid testing capabilities, up-conversion fluorescence lateral-flow immunoassay (LFA) can be an ideal solution to detect DARA interference.METHODS: An up-conversion fluorescence LFA strip was designed and constructed to perform semi-quantitative DARA testing in clinical samples. The LFA strip test was evaluated for limit of detection (LOD), dynamic range, and analytical interference.RESULTS: To demonstrate the clinical utility of the LFA strip, 43 SPEP-positive patient serum samples were tested for the presence of DARA, and the results exactly matched the DARA usage history in patient medical records.CONCLUSIONS: The performance of the up-conversion fluorescence LFA strip meets the purpose of clarifying DARA interference in SPEP results. It may be used as an independent and objective confirmation of the presence of DARA in clinical samples. The LFA strip offers a cost-effective rapid on-site test to check for DARA interference alongside standard SPEP equipment, which significantly improves the interpretation of ambiguous SPEP results involving DARA, and does not intervene the current SPEP workflow in clinical laboratory practice.

    View details for DOI 10.1016/j.cca.2024.119677

    View details for PubMedID 38636694

  • Transport of Full-Length Proteins through a Nanopore: One Step Closer to Single-Molecule Proteomics. Clinical chemistry Yeung, P. S., Luo, R. Y. 2024; 70 (2): 462-463

    View details for DOI 10.1093/clinchem/hvad201

    View details for PubMedID 38321876

  • Transport of Full-Length Proteins through a Nanopore: One Step Closer to Single-Molecule Proteomics CLINICAL CHEMISTRY Yeung, P. W., Luo, R. 2024; 70 (2): 456-457
  • Study of β1-transferrin and β2-transferrin using microprobe-capture in-emitter elution and high-resolution mass spectrometry. Scientific reports Luo, R. Y., Pfaffroth, C., Yang, S., Hoang, K., Yeung, P. S., Zehnder, J. L., Shi, R. Z. 2023; 13 (1): 14974


    Cerebrospinal fluid (CSF) leak can be diagnosed in clinical laboratories by detecting a diagnostic marker β2-transferrin (β2-Tf) in secretion samples. β2-Tf and the typical transferrin (Tf) proteoform in serum, β1-transferrin (β1-Tf), are Tf glycoforms. An innovative affinity capture technique for sample preparation, called microprobe-capture in-emitter elution (MPIE), was incorporated with high-resolution mass spectrometry (HR-MS) to study the Tf glycoforms and the primary structures of β1-Tf and β2-Tf. To implement MPIE, an analyte is first captured on the surface of a microprobe, and subsequently eluted from the microprobe inside an electrospray emitter. The capture process is monitored in real-time via next-generation biolayer interferometry (BLI). When electrospray is established from the emitter to a mass spectrometer, the analyte is immediately ionized via electrospray ionization (ESI) for HR-MS analysis. Serum, CSF, and secretion samples were analyzed using MPIE-ESI-MS. Based on the MPIE-ESI-MS results, the primary structures of β1-Tf and β2-Tf were elucidated. As Tf glycoforms, β1-Tf and β2-Tf share the amino acid sequence but contain varying N-glycans: (1) β1-Tf, the major serum-type Tf, has two G2S2 N-glycans on Asn413 and Asn611; and (2) β2-Tf, the major brain-type Tf, has an M5 N-glycan on Asn413 and a G0FB N-glycan on Asn611. The resolving power of the innovative MPIE-ESI-MS method was demonstrated in the study of β2-Tf as well as β1-Tf. Knowing the N-glycan structures on β2-Tf allows for the design of more novel test methods for β2-Tf in the future.

    View details for DOI 10.1038/s41598-023-42064-7

    View details for PubMedID 37696850

    View details for PubMedCentralID 345148

  • Mass spectrometry quantitation of immunosuppressive drugs in clinical specimens using online solid-phase extraction and accurate-mass full scan-single ion monitoring. Journal of mass spectrometry and advances in the clinical lab Yeung, P. S., Miller, P., Lai-Nyugen, T. B., Cheng, P., Ibrahim, A., Shi, R., Bowen, R. A., Luo, R. Y. 2023; 28: 99-104


    Introduction: Therapeutic drug monitoring (TDM) of immunosuppressants is essential for optimal care of transplant patients. Immunoassays and liquid chromatography-mass spectrometry (LC-MS) are the most commonly used methods for TDM. However, immunoassays can suffer from interference from heterophile antibodies and structurally similar drugs and metabolites. Additionally, nominal-mass LC-MS assays can be difficult to optimize and are limited in the number of detectable compounds.Objectives: The aim of this study was to implement a mass spectrometry-based test for immunosuppressant TDM using online solid-phase extraction (SPE) and accurate-mass full scan-single ion monitoring (FS-SIM) data acquisition mode.Methods: LC-MS analysis was performed on a TLX-2 multi-channel HPLC with a Q-Exactive Plus mass spectrometer. TurboFlow online SPE was used for sample clean up. The accurate-mass MS was set to positive electrospray ionization mode with FS-SIM for quantitation of tacrolimus, sirolimus, everolimus, and cyclosporine A. MS2 fragmentation pattern was used for compound confirmation.Results: The method was validated in terms of precision, analytical bias, limit of quantitation, linearity, carryover, sample stability, and interference. Quantitation of tacrolimus, sirolimus, everolimus, and cyclosporine A correlated well with results from an independent reference laboratory (r=0.926-0.984).Conclusions: Accurate-mass FS-SIM can be successfully utilized for immunosuppressant TDM with good correlation with results generated by standard methods. TurboFlow online SPE allows for a simple "protein crash and shoot" sample preparation protocol. Compared to traditional MRM, analyte quantitation by FS-SIM facilitates a streamlined assay optimization process.

    View details for DOI 10.1016/j.jmsacl.2023.03.002

    View details for PubMedID 36937810

  • Evaluation of a Rapid and Accessible Reverse Transcription-Quantitative PCR Approach for SARS-CoV-2 Variant of Concern Identification. Journal of clinical microbiology Yeung, P. S., Wang, H., Sibai, M., Solis, D., Yamamoto, F., Iwai, N., Jiang, B., Hammond, N., Truong, B., Bihon, S., Santos, S., Mar, M., Mai, C., Mfuh, K. O., Miller, J. A., Huang, C., Sahoo, M. K., Zehnder, J. L., Pinsky, B. A. 2022: e0017822


    The ability to distinguish between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) is of ongoing interest due to differences in transmissibility, responses to vaccination, clinical prognosis, and therapy. Although detailed genetic characterization requires whole-genome sequencing (WGS), targeted nucleic acid amplification tests can serve a complementary role in clinical settings, as they are more rapid and accessible than sequencing in most laboratories. We designed and analytically validated a two-reaction multiplex reverse transcription-quantitative PCR (RT-qPCR) assay targeting spike protein mutations L452R, E484K, and N501Y in reaction 1 and del69-70, K417N, and T478K in reaction 2. This assay had 95 to 100% agreement with WGS for 502 upper respiratory tract swab samples collected between 26 April 2021 and 1 August 2021, consisting of 43 Alpha, 2 Beta, 20 Gamma, 378 Delta, and 59 non-VOC infections. Validation in a separate group of 230 WGS-confirmed Omicron variant samples collected in December 2021 and January 2022 demonstrated 100% agreement. This RT-qPCR-based approach can be implemented in clinical laboratories already performing SARS-CoV-2 nucleic acid amplification tests to assist in local epidemiological surveillance and clinical decision-making.

    View details for DOI 10.1128/jcm.00178-22

    View details for PubMedID 35465708

  • Development and evaluation of an RT-qPCR for the identification of the SARS-CoV-2 Omicron variant. Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology Sibai, M., Wang, H., Yeung, P. S., Sahoo, M. K., Solis, D., Mfuh, K. O., Huang, C., Yamamoto, F., Pinsky, B. A. 2022; 148: 105101

    View details for DOI 10.1016/j.jcv.2022.105101

    View details for PubMedID 35151048