Review Article2022-01-01 Clinical Chemistry

Hormone Immunoassay Interference: A 2021 Update

Khaldoun Ghazal , Pharm., Ph.D., Severine Brabant , M.D., Dominique Prie , M.D., Ph.D., and Marie-Liesse Piketty , Pharm., Ph.D.

Ann Lab Med 2022; 42(1): 3-23

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Abstract : Immunoassays are powerful qualitative and quantitative analytical techniques. Since the first description of an immunoassay method in 1959, advances have been made in assay designs and analytical characteristics, opening the door for their widespread implementation in clinical laboratories. Clinical endocrinology is closely linked to laboratory medicine because hormone quantification is important for the diagnosis, treatment, and prognosis of endocrine disorders. Several interferences in immunoassays have been identified through the years; although some are no longer encountered in daily practice, cross-reaction, heterophile antibodies, biotin, and anti-analyte antibodies still cause problems. Newer interferences are also emerging with the development of new therapies. The interfering substance may be exogenous (e.g., a drug or substance absorbed by the patient) or endogenous (e.g., antibodies produced by the patient), and the bias caused by interference can be positive or negative. The consequences of interference can be deleterious when clinicians consider erroneous results to establish a diagnosis, leading to unnecessary explorations or inappropriate treatments. Clinical laboratories and manufacturers continue to investigate methods for the detection, elimination, and prevention of interferences. However, no system is completely devoid of such incidents. In this review, we focus on the analytical interferences encountered in daily practice and possible solutions for their detection or elimination.

Review Article2021-11-01 General Laboratory Medicine

Biomarkers for Prognosis and Treatment Response in COVID-19 Patients

Giulia Bivona , M.D., Luisa Agnello , Ph.D., and Marcello Ciaccio , M.D., Ph.D.

Ann Lab Med 2021; 41(6): 540-548

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Abstract : During a severe infection such as coronavirus disease 2019 (COVID-19), the level of almost all analytes can change, presenting a correlation with disease severity and survival; however, a biomarker cannot be translated into clinical practice for treatment guidance until it is proven to have a significant impact. Several studies have documented the association between COVID-19 severity and circulating levels of C-reactive protein (CRP) and interleukin-6, and the accuracy of the CRP level in predicting treatment responses has been evaluated. Moreover, promising findings on prothrombin and D-dimer have been reported. However, the clinical usefulness of these biomarkers in COVID-19 is far from proven. The burst of data generation during this pandemic has led to the publication of numerous studies with several notable drawbacks, weakening the strength of their findings. We provide an overview of the key findings of studies on biomarkers for the prognosis and treatment response in COVID-19 patients. We also highlight the main drawbacks of these studies that have limited the clinical use of these biomarkers.

Review Article2021-11-01 General Laboratory Medicine

Application of Single-Domain Antibodies (“Nanobodies”) to Laboratory Diagnosis

Tahir S. Pillay , MBChB., Ph.D. and Serge Muyldermans , Ph.D.

Ann Lab Med 2021; 41(6): 549-558

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Abstract : Antibodies have proven to be central in the development of diagnostic methods over decades, moving from polyclonal antibodies to the milestone development of monoclonal antibodies. Although monoclonal antibodies play a valuable role in diagnosis, their production is technically demanding and can be expensive. The large size of monoclonal antibodies (150 kDa) makes their re-engineering using recombinant methods a challenge. Single-domain antibodies, such as “nanobodies,” are a relatively new class of diagnostic probes that originated serendipitously during the assay of camel serum. The immune system of the camelid family (camels, llamas, and alpacas) has evolved uniquely to produce heavy-chain antibodies that contain a single monomeric variable antibody domain in a smaller functional unit of 12–15 kDa. Interestingly, the same biological phenomenon is observed in sharks. Since a single-domain antibody molecule is smaller than a conventional mammalian antibody, recombinant engineering and protein expression in vitro using bacterial production systems are much simpler. The entire gene encoding such an antibody can be cloned and expressed in vitro. Single-domain antibodies are very stable and heat-resistant, and hence do not require cold storage, especially when incorporated into a diagnostic kit. Their simple genetic structure allows easy re-engineering of the protein to introduce new antigen-binding characteristics or attach labels. Here, we review the applications of single-domain antibodies in laboratory diagnosis and discuss the future potential in this area.

Review Article2022-05-01 Diagnostic Hematology

Myelodysplastic Syndromes with Bone Marrow Fibrosis: An Update

Akriti G. Jain , M.D., Ling Zhang , M.D., John M. Bennett , M.D., and Rami Komrokji , M.D.

Ann Lab Med 2022; 42(3): 299-305

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Abstract : Myelodysplastic syndrome (MDS) is a diverse hematological malignancy with a wide spectrum of presentations and implications. Treatment strategies for patients with MDS heavily rely on prognostic scoring systems, such as the revised international prognostic scoring system (IPSS-R). Bone marrow fibrosis (BMF) has been identified as an independent risk factor for poor survival in patients with MDS, irrespective of the IPSS-R risk category. However, BMF is not widely included in scoring systems and is not always considered by clinicians when making treatment decisions for patients. In this review, we discuss the available literature about the presentation and prognosis of patients with MDS and concurrent BMF. The prognostic impact of BMF should be factored in when deciding on transplant candidacy, especially for intermediate-risk patients.

Review Article2022-09-01 Diagnostic Hematology

Unreliable Automated Complete Blood Count Results: Causes, Recognition, and Resolution

Gene Gulati, Ph.D., Guldeep Uppal, M.D., and Jerald Gong, M.D.

Ann Lab Med 2022; 42(5): 515-530

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Abstract : Automated hematology analyzers generate accurate complete blood counts (CBC) results on nearly all specimens. However, every laboratory encounters, at times, some specimens that yield no or inaccurate result(s) for one or more CBC parameters even when the analyzer is functioning properly and the manufacturer’s instructions are followed to the letter. Inaccurate results, which may adversely affect patient care, are clinically unreliable and require the attention of laboratory professionals. Laboratory professionals must recognize unreliable results, determine the possible cause(s), and be acquainted with the ways to obtain reliable results on such specimens. We present a concise overview of the known causes of unreliable automated CBC results, ways to recognize them, and means commonly utilized to obtain reliable results. Some examples of unreliable automated CBC results are also illustrated. Pertinent analyzer-specific information can be found in the manufacturers’ operating manuals.

Original Article2021-11-01 Diagnostic Immunology

Comparison of SARS-CoV-2 Antibody Responses and Seroconversion in COVID-19 Patients Using Twelve Commercial Immunoassays

Sojeong Yun , B.S., Ji Hyeong Ryu , M.S., Joo Hee Jang , B.S., Hyunjoo Bae , M.S., Seung-Hyo Yoo , M.T., Ae-Ran Choi , M.T., Sung Jin Jo , M.D., Jihyang Lim , M.D., Jehoon Lee , M.D., Hyejin Ryu , M.D., Sung-Yeon Cho , M.D., Dong-Gun Lee , M.D., Jongmin Lee , M.D., Seok Chan Kim , M.D., Yeon-Joon Park , M.D., Hyeyoung Lee , M.D., and Eun-Jee Oh , M.D.

Ann Lab Med 2021; 41(6): 577-587

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Abstract : Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody assays have high clinical utility in managing the pandemic. We compared antibody responses and seroconversion of coronavirus disease 2019 (COVID-19) patients using different immunoassays. Methods: We evaluated 12 commercial immunoassays, including three automated chemiluminescent immunoassays (Abbott, Roche, and Siemens), three enzyme immunoassays (Bio-Rad, Euroimmun, and Vircell), five lateral flow immunoassays (Boditech Med, SD biosensor, PCL, Sugentech, and Rapigen), and one surrogate neutralizing antibody assay (GenScript) in sequential samples from 49 COVID-19 patients and 10 seroconversion panels. Results: The positive percent agreement (PPA) of assays for a COVID-19 diagnosis ranged from 84.0% to 98.5% for all samples (>14 days after symptom onset), with IgM or IgA assays showing higher PPAs. Seroconversion responses varied across the assay type and disease severity. Assays targeting the spike or receptor-binding domain protein showed a tendency for early seroconversion detection and higher index values in patients with severe disease. Index values from SARS-CoV-2 binding antibody assays (three automated assays, one LFIA, and three EIAs) showed moderate to strong correlations with the neutralizing antibody percentage (r=0.517–0.874), and stronger correlations in patients with severe disease and in assays targeting spike protein. Agreement among the 12 assays was good (74.3%–96.4%) for detecting IgG or total antibodies. Conclusions: Positivity rates and seroconversion of SARS-CoV-2 antibodies vary depending on the assay kits, disease severity, and antigen target. This study contributes to a better understanding of antibody response in symptomatic COVID-19 patients using currently available assays.

Brief Communication2021-11-01 Clinical Microbiology

Clinical Performance of the Standard Q COVID-19 Rapid Antigen Test and Simulation of its Real-World Application in Korea

Jaehyeon Lee , M.D., So Yeon Kim , M.D., Hee Jae Huh , M.D., Namsu Kim , M.D., Heungsup Sung , M.D., Hyukmin Lee , M.D., Kyoung Ho Roh , M.D., Taek Soo Kim , M.D., and Ki Ho Hong , M.D.

Ann Lab Med 2021; 41(6): 588-592

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Abstract : The rapid antigen test (RAT) for coronavirus disease (COVID-19) represents a potent diagnostic method in situations of limited molecular testing resources. However, considerable performance variance has been reported with the RAT. We evaluated the clinical performance of Standard Q COVID-19 RAT (SQ-RAT; SD Biosensor, Suwon, Korea), the first RAT approved by the Korean Ministry of Food and Drug Safety. In total, 680 nasopharyngeal swabs previously tested using real-time reverse-transcription PCR (rRT-PCR) were retested using SQ-RAT. The clinical sensitivity of SQ-RAT relative to that of rRT-PCR was 28.7% for all specimens and was 81.4% for specimens with RNA-dependent RNA polymerase gene (RdRp) threshold cycle (Ct) values ≤23.37, which is the limit of detection of SQ-RAT. The specificity was 100%. The clinical sensitivity of SQ-RAT for COVID-19 diagnosis was assessed based on the Ct distribution at diagnosis of 33,294 COVID-19 cases in Korea extracted from the laboratory surveillance system of Korean Society for Laboratory Medicine. The clinical sensitivity of SQ-RAT for COVID-19 diagnosis in the Korean population was 41.8%. Considering the molecular testing capacity in Korea, use of the RAT for COVID-19 diagnosis appears to be limited.

Original Article2022-03-01 Clinical Microbiology

Clinical Differences in Patients Infected with Fusobacterium and Antimicrobial Susceptibility of Fusobacterium Isolates Recovered at a Tertiary-Care Hospital in Korea

Myungsook Kim , Ph.D., Shin Young Yun , M.D., Yunhee Lee , B.D., Hyukmin Lee , M.D., Dongeun Yong , M.D., Kyungwon Lee , M.D.

Ann Lab Med 2022; 42(2): 188-195

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Abstract : Background: Fusobacterium species are obligately anaerobic, gram-negative bacilli. Especially, F. nucleatum and F. necrophorum are highly relevant human pathogens. We investigated clinical differences in patients infected with Fusobacterium spp. and determined the antimicrobial susceptibility of Fusobacterium isolates. Methods: We collected clinical data of 86 patients from whom Fusobacterium spp. were isolated from clinical specimens at a tertiary-care hospital in Korea between 2003 and 2020. In total, 76 non-duplicated Fusobacterium isolates were selected for antimicrobial susceptibility testing by the agar dilution method, according to the Clinical and Laboratory Standards Institute guidelines (M11-A9). Results: F. nucleatum was most frequently isolated from blood cultures and was associated with hematologic malignancy, whereas F. necrophorum was mostly prevalent in head and neck infections. Anti-anaerobic agents were more commonly used to treat F. nucleatum and F. varium infections than to treat F. necrophorum infections. We observed no significant difference in mortality between patients infected with these species. All F. nucleatum and F. necrophorum isolates were susceptible to the antimicrobial agents tested. F. varium was resistant to clindamycin (48%) and moxifloxacin (24%), and F. mortiferum was resistant to penicillin G (22%) and ceftriaxone (67%). β-Lactamase activity was not detected. Conclusions: Despite the clinical differences among patients with clinically important Fusobacterium infections, there was no significant difference in the mortality rates. Some Fusobacterium spp. were resistant to penicillin G, ceftriaxone, clindamycin, or moxifloxacin. This study may provide clinically relevant data for implementing empirical treatment against Fusobacterium infections.

Review Article2022-05-01 Transfusion Medicine

Current State of Blood Management Services in Korea

Hyun Ok Kim , M.D., Ph.D.

Ann Lab Med 2022; 42(3): 306-313

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Abstract : Blood is lifesaving; however, it can neither be limitlessly acquired nor artificially produced. The supply and use of blood, as an invaluable biological commodity, necessitate systematic and rational management under governmental guidance to ensure safe and reliable transfusions. Despite Korea’s blood donation rate of 5.04%, which is higher than the 3.15% in high-income countries as reported by the WHO, the demand for blood exceeds the availability. This is due to the birthrate decline, dearth of young donors, and growing and aging recipient population. This review outlines the Korean blood management system, with a focus on blood service data from 2020, with the aim to delineate the current state of Korea’s blood management system and the policies established to address the imminent blood shortage. Each policy is described in detail to provide helpful information for blood management services in other countries.

Review Article2022-03-01 Clinical Chemistry

Review of the Use of Liquid Chromatography-Tandem Mass Spectrometry in Clinical Laboratories: Part I-Development

Brian A. Rappold , B.S.

Ann Lab Med 2022; 42(2): 121-140

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Abstract : The process of method development for a diagnostic assay based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) involves several disparate technologies and specialties. Additionally, method development details are typically not disclosed in journal publications. Method developers may need to search widely for pertinent information on their assay(s). This review summarizes the current practices and procedures in method development. Additionally, it probes aspects of method development that are generally not discussed, such as how exactly to calibrate an assay or where to place quality controls, using examples from the literature. This review intends to provide a comprehensive resource and induce critical thinking around the experiments for and execution of developing a clinically meaningful LC-MS/MS assay.