Definition of the upper reference limit for thyroglobulin antibodies according to the National Academy of Clinical Biochemistry guidelines: comparison of eleven different automated methods

SummaryThe upper limit of the TSH reference range is currently under discussion. In its recent guidelines, the National Academy of Clinical Biochemistry (NACB) recommended the use of ~2.5 mIU/L, rather than ~4 mIU/L, due to the fact that reference populations, on which the definition of the reference range is based, contain persons undergoing an initial phase of autoimmune thyroid disease. This will skew the upper reference limit of TSH. Ultrasonography, in addition to measurement of thyroid autoantibodies, should be used to exclude these persons. Objective: The present study investigates whether the NACB recommendation also applies for a region of mild iodine deficiency. Methods: According to NACB criteria, a reference population (713 persons) was defined out of a total study population of 1442. The TSH reference range was calculated in this reference group and in further subgroups by percentiles. The results were compared with the total study population and the NACB recommendation. All assays used were provided by BRAHMS Diagnostica AG, Hennigsdorf, Germany. Results: As expected, all median TSH values, excluding the median of the group with a hypoechogenic thyroid were close to 1.2 mIU/L. The 97.5th percentile in the reference population was 3.35 mIU/L. However, there was no difference compared to the total study population. Conclusion: The upper reference limit for TSH based on a reference population according to NACB criteria came down to 3.35 mIU/L, but not to ~2.5 mIU/L. Interestingly, there is no difference compared to the total study population.

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Definition of the upper reference limit of glycated albumin in blood donors from Italy

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2017-0179 ◽

2017 ◽

Vol 56 (1) ◽

Cited By ~ 20

Author(s):

Chiara Bellia ◽

Martina Zaninotto ◽

Chiara Cosma ◽

Luisa Agnello ◽

Bruna Lo Sasso ◽

...

Keyword(s):

Blood Donors ◽

Glycated Albumin ◽

Specific Reference ◽

Reference Limit ◽

Percentile Method ◽

The Mean ◽

Definition Of ◽

Upper Reference Limit ◽

Mean Glucose

AbstractBackground:Glycated Albumin (GA) has been proposed as a short-term indicator of glycemic homeostasis. The aim of this study is to describe the distribution of GA in a large sample of blood donors from Italy to evaluate whether demographic features, namely age and sex, could influence GA levels and define specific reference limits.Methods:The study included 1334 Italian blood donors. GA was measured using an enzymatic method (quantILab Glycated Albumin, IL Werfen, Germany). The upper reference limit (URL) was calculated using the non-parametric percentile method.Results:A modest, although significant, increase of GA was observed in relation to age (p<0.001), especially in males, where the differences were more pronounced (p<0.001 in males, p=0.003 in females). Slight differences were documented based on sex (12% [11.3–12.8] in males; 12.2% [11.4–13.1] in females; p=0.01). After excluding individuals with fasting plasma glucose ≥7 mmol/L, the calculated GA URL was 14.5% (95% CI: 14.3–14.7). Subjects with GA>14.5% presented a mean age of 48.4±12.2 years, 66.7% were males and the mean glucose was 6.88±2.5 mmol/L.Conclusions:GA in Caucasians shows a similar increasing trend at older ages documented in other ethnicities. The definition of the URL in this population could be useful for both clinical studies, which will clarify the role of GA for diagnosing and monitoring diabetes, and will encourage the introduction of GA in clinical practice.

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Emergency department triage of patients with acute chest pain: definition of cardiac troponin I decisional value to manage patients without electrocardiographic evidence of ischemia

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm.2004.094 ◽

2004 ◽

Vol 42 (5) ◽

Cited By ~ 1

Author(s):

Pascale Beyne ◽

Erik Bouvier ◽

Patrick Werner ◽

Pierre Bourgoin ◽

Damien Logeart ◽

...

Keyword(s):

Chest Pain ◽

Cardiac Troponin ◽

Troponin I ◽

Acute Chest Pain ◽

Final Diagnosis ◽

Cardiac Troponin I ◽

Reference Limit ◽

Coronary Syndrome ◽

Definition Of ◽

Upper Reference Limit

AbstractThe aim of this study was to define the use of a new cardiac troponin I (cTnI) assay for emergency patients with chest pain and no specific electrocardiographic changes consistent with the presence of ischemia. Patients (n=106) admitted in Emergency/Cardiology Departments for chest pain and suspicion of acute coronary syndrome (ACS) were randomized into two diagnosis groups (ACS or non-ACS) by two independent cardiologists. cTnI measurements were performed at admission, and 6 hours and 12 hours later with a new generation assay (Access AccuTnI, Beckman Coulter). Using an upper reference limit of 0.04 μg/l, 27 patients had a cTnI elevation not related to the final diagnosis of ischemia; the positive predictive value (PPV) was 67% with specificity 48%. The decisional value was re-defined and set at 0.16 μg/l, a concentration corresponding to the 99th percentile of the non-ACS patient group. Precision (coefficient of variation) was 8% at this level, PPV 97% and specificity 98%. This new decisional value is now used in our institution and could be included in standard care guidelines to improve the management of patients presenting chest pain in emergency departments.

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The universal definition of myocardial infarction

10.1093/med/9780199687039.003.0041 ◽

2015 ◽

Cited By ~ 7

Author(s):

Kristian Thygesen ◽

Joseph S Alpert ◽

Allan S Jaffe ◽

Harvey D White

Keyword(s):

Myocardial Infarction ◽

Wall Motion ◽

Regional Wall Motion ◽

Cardiac Biomarkers ◽

Regional Wall ◽

Reference Limit ◽

Electrocardiographic Changes ◽

Universal Definition ◽

Definition Of ◽

Upper Reference Limit

Myocardial infarction is defined pathologically as myocyte necrosis due to prolonged ischaemia. These conditions are met when there is a detection of a rise and/or fall of cardiac biomarkers, preferably troponins, with at least one value above the 99th percentile of the upper reference limit, together with evidence of myocardial ischaemia, as recognized by at least one of the following: symptoms of ischaemia, electrocardiographic changes of new ischaemia, the development of pathological Q waves, imaging evidence of a new loss of viable myocardium or new regional wall motion abnormality, or the identification of an intracoronary thrombus by angiography or autopsy.

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Universal definition of MI: Above 99 percentile of upper reference limit (URL) for hs-cTn: Yes, but which URL?

The American Journal of Emergency Medicine ◽

10.1016/j.ajem.2018.12.052 ◽

2019 ◽

Vol 37 (3) ◽

pp. 510 ◽

Cited By ~ 2

Author(s):

Mehmet Agirbasli

Keyword(s):

Reference Limit ◽

Universal Definition ◽

Definition Of ◽

Upper Reference Limit

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The universal definition of myocardial infarction

The ESC Textbook of Intensive and Acute Cardiovascular Care ◽

10.1093/med/9780198849346.003.0038 ◽

2021 ◽

pp. 463-478

Author(s):

Kristian Thygesen ◽

Joseph S Alpert ◽

Allan S Jaffe ◽

Harvey D White

Keyword(s):

Myocardial Infarction ◽

Myocardial Ischaemia ◽

Regional Wall Motion ◽

Cardiac Biomarkers ◽

Regional Wall ◽

Reference Limit ◽

Universal Definition ◽

Definition Of ◽

Upper Reference Limit ◽

Cardiac Troponins

Myocardial infarction is defined by the presence of myocardial injury detected by abnormal cardiac biomarkers in the setting of acute clinical myocardial ischaemia. These conditions are met when there is a detection of a rise and/or fall of cardiac biomarkers, preferably cardiac troponins, with at least one value above the 99th percentile of the upper reference limit together with evidence of acute clinical myocardial ischaemia as recognized by at least one of the following: symptoms of ischaemia, ECG changes of new ischaemia, development of pathological Q waves, imaging evidence of new loss of viable myocardium or new regional wall motion abnormality, or identification of an intracoronary thrombus by angiography or autopsy.

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Increased canine pancreatic lipase immunoreactivity (cPLI) and 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6′-methylresorufin) ester (DGGR) lipase in dogs with evidence of portal hypertension and normal pancreatic histology: a pilot study

Journal of Veterinary Diagnostic Investigation ◽

10.1177/10406387211003987 ◽

2021 ◽

pp. 104063872110039

Author(s):

Gonçalo Serrano ◽

Dominique Paepe ◽

Tim Williams ◽

Penny Watson

Keyword(s):

Portal Hypertension ◽

Liver Disease ◽

Pilot Study ◽

Pancreatic Lipase ◽

Glutaric Acid ◽

Inclusion Criteria ◽

Reference Limit ◽

Clinical Presentations ◽

Upper Reference Limit

The clinical presentations of both liver disease and pancreatitis are nonspecific and overlapping, which may cause difficulty in diagnosis. In our retrospective pilot study, we assessed whether dogs with evidence of portal hypertension and absence of pancreatitis on pancreatic histology have increases in canine pancreatic lipase immunoreactivity (cPLI) and 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6′-methylresorufin) ester (DGGR) lipase. We included dogs that had been presented between 2008 and 2019 if they had normal pancreatic histology, histologically confirmed hepatopathy, and if canine pancreas-specific lipase (Spec cPL; Idexx) or DGGR lipase had been measured. Only dogs with portal hypertension were included. Six dogs fulfilled the inclusion criteria. Four of 6 and 2 of 6 dogs had Spec cPL and DGGR lipase exceeding the upper reference limit, respectively. From the 4 dogs with increased Spec cPL, 2 had concentrations of 200–400 µg/L and 2 had concentrations ≥ 400 µg/L. Our results suggest that canine portal hypertension might lead to increased Spec cPL and DGGR lipase values in the absence of pancreatitis on histology. Until more evidence in a larger number of dogs with portal hypertension is available, both tests should be interpreted cautiously in the presence of portal hypertension.

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Clinical and analytical evaluation of kits for measurement of creatine kinase isoenzyme MB.

Clinical Chemistry ◽

10.1093/clinchem/32.1.186 ◽

1986 ◽

Vol 32 (1) ◽

pp. 186-191 ◽

Cited By ~ 12

Author(s):

T R Koch ◽

U J Mehta ◽

H C Nipper

Keyword(s):

Creatine Kinase ◽

Clinical Performance ◽

Reference Population ◽

Reference Ranges ◽

Diagnostic Specificity ◽

Electrophoretic Method ◽

Reference Limit ◽

Coronary Care ◽

Upper Reference Limit ◽

Creatine Kinase Isoenzyme Mb

Abstract We studied the analytical and clinical performance of six methods for creatine kinase (EC 2.7.3.2) isoenzyme MB (CK-MB): three immunoassays (Behring, Hybritech, and International Immunoassay Labs); one immunoinhibition assay (Roche); one immunoinhibition/column method (Du Pont); and one electrophoretic method (Beckman). Between-day precision for all kits was poor at the upper reference limit. All methods gave results linearly related to CK-MB concentration and all were free from CK-MM, CK-BB, and adenylate kinase interference. Only the Du Pont method was adversely affected by atypical isoenzymes. For diagnosis of acute myocardial infarction in a coronary care population (n = 40; prevalence = 45%), all methods were approximately 95% efficient, when appropriate reference criteria were used. Some manufacturers fail to provide data for an appropriate (acutely ill, non-infarct) reference population; decreased diagnostic specificity may result from use of reference ranges based on results for healthy subjects. Expression of CK-MB as a percent of total CK degrades efficiency unless total CK is markedly increased.

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Neuroblastoma—When are Urinary Catecholamines and Their Metabolites ‘Normal’?

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456328802500604 ◽

1988 ◽

Vol 25 (6) ◽

pp. 620-626 ◽

Cited By ~ 5

Author(s):

D J Worthington ◽

E M Hammond ◽

B B Eldeeb ◽

A Green ◽

G M Addison ◽

...

Keyword(s):

Urinary Excretion ◽

The Other ◽

Published Data ◽

Single Test ◽

Creatinine Concentration ◽

Urinary Catecholamines ◽

Clinical Sensitivity ◽

Reference Limit ◽

Upper Reference Limit ◽

The Individual

The overproduction of catecholamines and their metabolites is a well recognised feature of neuroblastoma. Published data are scarce for their urinary excretion in children with neuroblastoma and in ill children in whom this diagnosis may be considered. We have determined a graphical upper reference limit for total catecholamines, total metadrenalines and HMMA in urine, expressed as a ratio to the creatinine concentration, for a group of 174 children with neuroblastoma and 704 hospitalised children with other disorders. This graph has been determined by examining the overlap region between the results for the two groups of children and avoids the irregularities caused by statistical outliers. The sensitivity and specificity of the individual tests indicate that total catecholamines is marginally the best single test to perform when trying to diagnose neuroblastoma, with the best clinical sensitivity being achieved by examining both total catecholamines and HMMA. Only two of the 174 children with neuroblastoma would not have been detected using these two tests. Total metadrenalines did not appear to add any further information and could be dropped from the repertoire in favour of the other two measurements.

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