Clinical Biochemistry Laboratory Medicine Practice Research Articles

Serum thyroid hormone reference intervals in the apparently healthy individuals of Zhengzhou area of China.

This study aimed to establish reference intervals for serum thyroid hormones [serum thyroid-stimulating hormone (TSH), triiodothyronine (TT3), thyroxine (TT4), free triiodothyronine (FT3), and free thyroxine (FT4)] in apparently healthy individuals living in Zhengzhou. According to the requirement for laboratory support for the diagnosis and monitoring of thyroid diseases in the National Academy of Clinical Biochemistry (NACB) laboratory medicine practice guidelines, a total of 211 apparently healthy individuals were enrolled (94 men, 117 women, 23-77 years old) from Zhengzhou for measurement of serum levels of TSH, TT3, TT4, FT3, and FT4 by using the Siemens ADVIA Centaur XP analyzer. All markers were analyzed across gender- and age-specific groups by using the t-test and ANOVA. The reference intervals of all markers were determined by P2.5-P97.5. We detected gender-associated statistical significances for TT3, TT4, FT3, and FT4 (t=3.299, 2.141, 5.868, 5.358; P<0.05), but not for TSH (t=-1.776, P>0.05). Correlation analysis showed that all markers were negatively correlated with age (P>0.05). The new reference intervals for TT3, TT4, FT3, FT4, and TSH were established: 0.76-1.38 ng/mL, 5.96-11.27 μg/dL, 3.88-5.59 pM, 11.69-18.84 pM, 0.89-5.93 μIU/mL, respectively. In conclusion, we added a new database of reference intervals of the serum thyroid hormones for the Chinese adult population.

The AGREE II Instrument Is Helpful for Creation of National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines

To the Editor: We commend Don-Wauchope et al., who assessed 11 National Academy of Clinical Biochemistry (NACB)1 laboratory medicine practice guidelines (LMPGs) with the AGREE II (Appraisal of Guidelines for Research and Evaluation II) instrument (1), and we thank Bossuyt for his accompanying editorial (2). The results of this study are helpful but are not unexpected. These LMPGs were developed over several years. The 8 nonarchived LMPGs published in the past 5 years used 4 different systems for grading and weighting practice recommendations. One system that several LMPG committees have used is a modified US Preventive Services Task Force (USPSTF) system. A second system used for 2 LMPGs was that of the American College of Cardiology and the American Heart Association. At times, NACB LMPG committees have used clinical societies' systems when these groups are primary collaborators in LMPG development, as well as significant end users of the LMPG. A third system created by the authors of 3 LMPGs focused on tumor marker tests. This unique system was developed by LMPG members who felt that considerable heterogeneity in clinical oncology practice guidelines failed to indicate a preference in any clinical society's system. Finally, authors of the most recent diabetes …

Room for Improvement in National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines

Practice guidelines are everywhere in healthcare. They have been around for decades, but their development, dissemination, and—possibly—their use skyrocketed in the 1990s. At that time, guidelines were positioned at the crossroads of 2 developments. One was the arrival of an era of assessment and accountability in healthcare. Undesirable variation in practice, spiraling healthcare costs, and concerns about the overuse and underuse of services encouraged professionals to take action. The other was the increasing belief that clinical-practice and healthcare policy decisions should be guided by the best available evidence, a goal increasingly more difficult to achieve at the level of the individual, given the daunting number of medical journals and the avalanche of studies reported in them. Evidence-based practice guidelines were seen as helpful in tackling these challenges, and professional societies, government panels, and other groups increasingly began developing recommendations to assist healthcare professionals in delivering appropriate healthcare. Soon, guidelines were ubiquitous in practice and policy, and their rapid production and promulgation created a new problem: information overload. Not only was the sheer number of guidelines problematic, but guideline documents also varied considerably in form and appearance—from brief lists of dos and don'ts to lengthy documents of textbook-level completeness that summarized the state of the art in the field. This variability was a reason for concern, because the promotion of flawed guidelines could encourage or even institutionalize the delivery of ineffective, harmful, or wasteful interventions (1). In a typical “early days” process of guideline development, a group of invited experts would gather around a conference table to develop recommendations based on their understanding of the scientific evidence, their knowledge of the field, and their opinion. A formal methodology for evaluating the evidence was not always followed, and similarly absent were procedures for the consensus process. Given the vulnerability of the …

Preanalytic conditions of the C-reactive protein are of paramount importance to use as a predictor of cardiovascular disease in clinical practice

We read the article by Wu et al. [1] about of the intra-individual variability of high-sensitivity C-reactive protein (hsCRP) in a cohort of Chinese adults. They recruited a large population (44,140 males and 12,078 females) inwhich blood samples were obtained during morning. The authors conclude that the age and gender are factors that influenced the hsCRP level. However, in the present article we saw an additional potential limitation of the study: they have not determined the hsCRP along a 24-hour period to eliminate the possible influence of circadian rhythms. Many epidemiological studies have demonstrated that hsCRP, a biomarker of inflammation, is an important prognostic factor for the future occurrence of major cardiovascular events, both in patients with known cardiovascular disease and apparently in healthy subjects [2,3]. The 2009 National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines included and endorsed the use of hsCRP as a novel means by which to identify individuals who are at risk for vascular disease [4]. Circulating biomarkers are subject to variability arising from sampling procedures andbiologic variation, and this variabilitymust be determined and adjusted for in the interpretation of laboratory results. Diurnal variation may be an important source of heterogeneity or bias, and standardization for sampling time may be important in populationbased studies, as well as, in using these variables for additional coronary heart disease risk prediction in individuals [5–8]. The available data on diurnal variations of hsCRP levels in healthy subjects are few and controversial. We have demonstrated absence of diurnal variation of hsCRP levels, when blood samples were collected at 9:00 AM (light period) and 2:00 AM (dark period) from 70 healthy subjects [9]. Previously, Meier-Ewert and colleagues found no diurnal variation in hsCRP samples that were taken hourly from 13 healthy subjects [10]. In other study of hsCRP, D-dimer, tissue plasminogen activator, and von Willebrand factor in a middle-aged population showed diurnal variation as high as 34% in hsCRP, with maximum hsCRP levels observed at 3:00 PM. However, that study was limited in that hsCRP was measured between 9:00 AM and 10:00 PM [11]. Moreover, recently Koc and colleagues [12] demonstrated a variation of 86% of hsCRP in 30 subjects who had normal coronary arteries at 6hour intervals over 24-hour period. Wu et al. have discussed in their manuscript that the age and environmental variables, such as lipid levels, blood pressure, obesity and diabetesmellitus can contribute to the variation of hsCRP [1,13]. However, with the items mentioned above, we believe that the diurnal variation should be taken into account as a control variable in multivariate regression models. In summary, hsCRP represents the most extensively studiedproinflammatorymolecule, but additional effort is requiredon the part of the investigators to manage standardization of methodology and to determine cost-effective timing and frequency of measurements. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology (Shewan and Coats 2010;144:1–2).

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Liver, Bladder, Cervical, and Gastric Cancers

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Liver, Bladder, Cervical, and Gastric Cancers

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Liver, Bladder, Cervical, and Gastric Cancers

Updated National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed. Published reports relevant to use of tumor markers for 4 cancer sites--liver, bladder, cervical, and gastric--were critically reviewed. Alpha-fetoprotein (AFP) may be used in conjunction with abdominal ultrasound for early detection of hepatocellular carcinoma (HCC) in patients with chronic hepatitis or cirrhosis associated with hepatitis B or C virus infection. AFP concentrations >200 microg/L in cirrhotic patients with typical hypervascular lesions >2 cm in size are consistent with HCC. After a diagnosis of HCC, posttreatment monitoring with AFP is recommended as an adjunct to imaging, especially in the absence of measurable disease. Although several urine markers have been proposed for bladder cancer, none at present can replace routine cystoscopy and cytology in the management of patients with this malignancy. Some may, however, be used as complementary adjuncts to direct more effective use of clinical procedures. Although carcinoembryonic antigen and CA 19-9 have been proposed for use gastric cancer and squamous cell carcinoma antigen for use in cervical cancer, none of these markers can currently be recommended for routine clinical use. Implementation of these recommendations should encourage optimal use of tumor markers for patients with liver, bladder, cervical, or gastric cancers.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines: Follow-Up Testing for Metabolic Disease Identified by Expanded Newborn Screening Using Tandem Mass Spectrometry; Executive Summary

Almost all newborns in the US are screened at birth for multiple inborn errors of metabolism using tandem mass spectrometry. Screening tests are designed to be sufficiently sensitive so that cases are not missed. The NACB recognized a need for standard guidelines for laboratory confirmation of a positive newborn screen such that all babies would benefit from equal and optimal follow-up by confirmatory testing. A committee was formed to review available data pertaining to confirmatory testing. The committee evaluated previously published guidelines, published methodological and clinical studies, clinical case reports, and expert opinion to support optimal confirmatory testing. Grading was based on guidelines adopted from criteria derived from the US Preventive Services Task Force and on the strength of recommendations and the quality of the evidence. Three primary methods of analyte measurement were evaluated for confirmatory testing including measurement of amino acids, organic acids, and carnitine esters. The committee graded the evidence for diagnostic utility of each test for the screened conditions. Ample data and experience were available to make strong recommendations for the practice of analyzing amino acids, organic acids, and acylcarnitines. Likewise, strong recommendations were made for the follow-up test menu for many disorders, particularly those with highest prevalence. Fewer data exist to determine the impact of newborn screening on patient outcomes in all but a few disorders. The guidelines also provide an assessment of developing technology that will fuel a refinement of current practice and ultimate expansion of the diseases detectable by tandem mass spectrometry. Guidelines are provided for optimal follow-up testing for positive newborn screens using tandem mass spectrometry. The committee regards these tests as reliable and currently optimal for follow-up testing. .

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines: Emerging Biomarkers for Primary Prevention of Cardiovascular Disease

Heart disease and stroke continue to be the leading causes of death in the US. As a result, investigators continue to look for new and emerging biomarkers of disease risk. Because many of these emerging biomarkers are not as well documented as those of conventional lipid and lipoprotein risk factors, their value in clinical practice needs to be critically appraised and appropriate guidelines developed for their proposed use. The National Academy of Clinical Biochemistry (NACB) convened a multidisciplinary expert panel to develop laboratory medicine practice guidelines for a selected subset of these emerging risk factors as applied in a primary prevention setting of heart disease and stroke. The NACB expert panel selected lipoprotein subclasses and particle concentration, lipoprotein(a), apolipoproteins A-I and B, high sensitivity C-reactive protein (hsCRP), fibrinogen, white blood cell count, homocysteine, B-type natriuretic peptide (BNP), N-terminal proBNP (NT-proBNP), and markers of renal function as biomarkers that fell within the scope of these guidelines. Based on a thorough review of the published literature, only hsCRP met all of the stated criteria required for acceptance as a biomarker for risk assessment in primary prevention.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Testicular, Prostate, Colorectal, Breast, and Ovarian Cancers

Updated National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed. Published reports relevant to use of tumor markers for 5 cancer sites--testicular, prostate, colorectal, breast, and ovarian--were critically reviewed. For testicular cancer, alpha-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase are recommended for diagnosis/case finding, staging, prognosis determination, recurrence detection, and therapy monitoring. alpha-Fetoprotein is also recommended for differential diagnosis of nonseminomatous and seminomatous germ cell tumors. Prostate-specific antigen (PSA) is not recommended for prostate cancer screening, but may be used for detecting disease recurrence and monitoring therapy. Free PSA measurement data are useful for distinguishing malignant from benign prostatic disease when total PSA is <10 microg/L. In colorectal cancer, carcinoembryonic antigen is recommended (with some caveats) for prognosis determination, postoperative surveillance, and therapy monitoring in advanced disease. Fecal occult blood testing may be used for screening asymptomatic adults 50 years or older. For breast cancer, estrogen and progesterone receptors are mandatory for predicting response to hormone therapy, human epidermal growth factor receptor-2 measurement is mandatory for predicting response to trastuzumab, and urokinase plasminogen activator/plasminogen activator inhibitor 1 may be used for determining prognosis in lymph node-negative patients. CA15-3/BR27-29 or carcinoembryonic antigen may be used for therapy monitoring in advanced disease. CA125 is recommended (with transvaginal ultrasound) for early detection of ovarian cancer in women at high risk for this disease. CA125 is also recommended for differential diagnosis of suspicious pelvic masses in postmenopausal women, as well as for detection of recurrence, monitoring of therapy, and determination of prognosis in women with ovarian cancer. Implementation of these recommendations should encourage optimal use of tumor markers.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for the Use of Tumor Markers

The National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for Use of Tumor Markers are intended to encourage more appropriate use of tumor marker tests by primary care physicians, hospital physicians and surgeons, specialist oncologists, and other health professionals. This introduction accompanies the e-publication of 2 reports summarizing NACB Quality Requirements for use of tumor markers in clinical practice (1) and NACB Guidelines for use of tumor markers in testicular, prostate, colorectal, breast, and ovarian cancers (2). Two further reports will follow, summarizing the NACB Guidelines for use of tumor markers in liver, pancreatic, gastric, bladder, and cervical cancers and the NACB Guidelines for use of tumor markers in parathyroid, thyroid, neuroendocrine and lung cancers, monoclonal gammopathies, and melanoma. Here we report the updating and extension of practice guidelines first proposed in 2002 (3). Undertaken under the direction of a steering committee appointed by the NACB (Table 1⇓ ), this process involved consideration of 16 specific cancer sites, together with quality requirements for well-established tumor markers and tumor markers being developed by use of new technologies (Table 2⇓ ). With its wide scope, this project is one of the most comprehensive and complex of its type to date. The draft guidelines were posted on the NACB website in July 2005 and were presented as an EduTrak at the 2005 Joint AACC/IFCC Annual meeting in Orlando, Florida. Informed comment was also actively sought from individuals, organizations, and other interested parties. View this table: Table 1. Steering committee for NACB Laboratory Medicine Practice Guidelines on Use of Tumor Markers in clinical practice. View this table: Table 2. Subjects and subcommittee members for NACB Laboratory Medicine Practice Guidelines on Use of Tumor Markers in clinical practice. Nineteen subcommittees developed draft guidelines (Table 2⇑ ). Subcommittee members included individuals with extensive expertise in the science, technology, and clinical practice …

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Clinical Practice: Quality Requirements1

This report presents updated National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines summarizing quality requirements for the use of tumor markers. One subcommittee developed guidelines for analytical quality relevant to serum and tissue-based tumor markers in current clinical practice. Two other subcommittees formulated recommendations particularly relevant to the developing technologies of microarrays and mass spectrometry. Prerequisites for optimal use of tumor markers in routine practice include formulation of the correct clinical questions to ensure selection of the appropriate test, adherence to good clinical and laboratory practices (e.g., minimization of the risk of incorrect patient and/or specimen identification, tube type, or timing), use of internationally standardized and well-characterized methods, careful adherence to manufacturer instructions, and proactive and timely reactions to information derived from both internal QC and proficiency-testing specimens. Highly desirable procedures include those designed to minimize the risk of the reporting of erroneous results attributable to interferences such as heterophilic antibodies or hook effects, to facilitate the provision of informative clinical reports (e.g., cumulative and/or graphical reports, appropriately derived reference intervals, and interpretative comments), and when possible to integrate these reports with other patient information through electronic health records. Also mandatory is extensive validation encompassing all stages of analysis before introduction of new technologies such as microarrays and mass spectrometry. Provision of high-quality tumor marker services is facilitated by dialogue involving researchers, diagnostic companies, clinical and laboratory users, and regulatory agencies. Implementation of these recommendations, adapted to local practice, should encourage optimization of the clinical use of tumor markers.

Biomarker Release After Percutaneous Coronary Intervention

Cardiac biomarkers of necrosis provide clinicians with important “messages” from the heart. They are released into the interstitium of the myocardium after loss of the integrity of cardiac myocyte membranes. The pattern of the rise and fall of an individual biomarker (ie, its release kinetics) depends on its intracellular location in the myocyte, molecular weight, and clearance from the interstitium of the myocardium and ultimately the circulation.1 Cardiac biomarkers play an integral role in the clinical diagnosis of myocardial infarction (MI). Referring to the spontaneous occurrence of MI in patients, the World Health Organization required that at least 2 of the following be present to fulfill the criteria for MI: a history of ischemia-type chest discomfort, evolutionary changes on serially obtained ECG tracings, and a rise and fall in serum cardiac markers.2 Article see p 10 See Editorial Circulation . 2008;118:609–611 See Article Circulation . 2008;118:632–638 Several dramatic advances have occurred in the biomarker component of the diagnosis of MI. Analytes with greater specificity for the myocardium were introduced into clinical medicine, with creatine kinase-MB replacing total creatine kinase and subsequently cardiac-specific troponins replacing creatine kinase-MB as the biomarker of choice for diagnosing MI.3 Assay technology improved as clinical chemists moved from enzymatic activity assays for CK to highly specific immunoassays that can detect progressively smaller concentrations of cardiac troponins in the peripheral circulation.4 Although ST-elevation MI (STEMI) is easily identified on the 12-lead ECG, we now recognize that many patients previously diagnosed with unstable angina are more properly diagnosed as having non–ST-elevation MI (NSTEMI) on the basis of the detection of elevated levels of cardiac troponins in their blood.5 Cardiac biomarkers are used as a rough guide to the extent of myocardial necrosis. The higher the peak biomarker level after STEMI, the larger the …

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines

AbstractGuidelines for the preanalytical, analytical, and postanalytical phases of cardiac biomarker testing at point of care (POC) are presented. At initiation, stakeholders including emergency medicine, cardiology, primary care, and laboratory medicine should work collaboratively to develop system

The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Point of Care pH Testing

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The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Point of Care Infectious Disease Testing

The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Point of Care Infectious Disease Testing

The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Intraoperative Parathyroid Hormone

The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Intraoperative Parathyroid Hormone

The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Occult Blood Testing

The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Occult Blood Testing

The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines

Reprints: James H. Nichols, PhD, DABCC, FACB, Clinical Chemistry, Baystate Health, 759 Chestnut St, Springfield, MA 01199 (e-mail: [email protected]).

The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Point of Care Coagulation Testing

The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Point of Care Coagulation Testing

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Utilization of Biochemical Markers in Heart Failure: Preamble

The National Academy of Clinical Biochemistry’s (NACB) Laboratory Medicine Practice Guidelines (LMPG) for use of cardiac markers were published in July of 1999.1 The focus of this initial document was biomarkers of acute coronary syndromes; however, in the years since 1999, the natriuretic peptide B-type natriuretic peptide and its inert co-metabolite N-terminal proB-type natriuretic peptide have become available, and much knowledge has accumulated about their clinical utilization in the context of heart failure and hemodynamic …