scholarly journals Global FT4 immunoassay standardization: an expert opinion review

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Juergen Kratzsch ◽  
Nikola A. Baumann ◽  
Ferruccio Ceriotti ◽  
Zhong X. Lu ◽  
Matthias Schott ◽  
...  
Keyword(s):  
Clinical Chemistry ◽  
Method Comparison ◽  
Clinical Decision ◽  
Reference Intervals ◽  
Clinical Impact ◽  
Specific Reference ◽  
Thyroid Function Tests ◽  
Global Standardization ◽  
Collaborative Efforts ◽  
Clinical Decision Limits

Abstract Objectives Results can vary between different free thyroxine (FT4) assays; global standardization would improve comparability of results between laboratories, allowing development of common clinical decision limits in evidence-based guidelines. Content We summarize the path to standardization of FT4 assays, and challenges associated with FT4 testing in special populations, including the need for collaborative efforts toward establishing population-specific reference intervals. The International Federation of Clinical Chemistry and Laboratory Medicine Committee for Standardization of Thyroid Function Tests has undertaken FT4 immunoassay method comparison and recalibration studies and developed a reference measurement procedure that is currently being validated. Further studies are needed to establish common reference intervals/clinical decision limits. Standardization of FT4 assays will change test results substantially; therefore, a major education program will be required to ensure stakeholders are aware of the benefits of FT4 standardization, planned transition procedure, and potential clinical impact of the changes. Assay recalibration by manufacturers and approval process simplification by regulatory authorities will help minimize the clinical impact of standardization. Summary Significant progress has been made toward standardization of FT4 testing, but technical and logistical challenges remain. Outlook Collaborative efforts by manufacturers, laboratories, and clinicians are required to achieve successful global standardization of the FT4 assays.

Reference intervals for neonatal thyroid function tests in the first 7 days of life

2018 ◽  
Vol 31 (10) ◽  
pp. 1113-1116 ◽  
Author(s):  
Michelle S. Jayasuriya ◽  
Kay W. Choy ◽  
Lit K. Chin ◽  
James Doery ◽  
Alice Stewart ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Medical Records ◽  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Primary Hypothyroidism ◽  
Specific Reference ◽  
Rapid Decline ◽  
Thyroid Function Tests ◽  
Accurate Identification ◽  
Neonatal Hypothyroidism

Abstract Background: Prompt intervention can prevent permanent adverse neurological effects caused by neonatal hypothyroidism. Thyroid function changes rapidly in the first few days of life but well-defined age-specific reference intervals (RIs) for thyroid-stimulating hormone (TSH), free thyroxine (FT4) and free tri-iodothyronine (FT3) are not available to aid interpretation. We developed hour-based RIs using data mining. Methods: All TSH, FT4 and FT3 results with date and time of collection from neonates aged <7 days during 2005–2015 were extracted from the Monash Pathology database. Neonates with more than one episode of testing or with known primary hypothyroidism, identified by treating physicians or from medical records, were excluded from the analysis. The date and time of birth were obtained from the medical records. Results: Of the 728 neonates qualifying for the study, 569 had time of birth available. All 569 had TSH, 415 had FT4 and 146 had FT3 results. For age ≤24 h, 25–48 h, 49–72 h, 73–96 h, 97–120 h, 121–144 h and 145–168 h of life, the TSH RIs (2.5th–97.5th) (mIU/L) were 4.1–40.2, 3.2–29.6, 2.6–17.3, 2.2–14.7, 1.8–14.2, 1.4–12.7 and 1.0–8.3, respectively; the FT4 RIs (mean ± 2 standard deviation [SD]) (pmol/L) were 15.3–43.6, 14.7–53.2, 16.5–45.5, 17.8–39.4, 15.3–32.1, 14.5–32.6 and 13.9–30.9, respectively; the FT3 RIs (mean±2 SD) (pmol/L) were 5.0–9.4, 4.1–9.1, 2.8–7.8, 2.9–7.8, 3.5–7.2, 3.4–8.0 and 3.8–7.9, respectively. Conclusions: TSH and FT4 were substantially high in the first 24 h after birth followed by a rapid decline over the subsequent 168 h. Use of hour-based RIs in newborns allows for more accurate identification of neonates who are at risk of hypothyroidism.

scholarly journals Early pregnancy reference intervals; 29 serum analytes from 4 to 12 weeks’ gestation in naturally conceived and uncomplicated pregnancies resulting in live births

2019 ◽  
Vol 57 (12) ◽  
pp. 1956-1967 ◽  
Author(s):  
Jesper Friis Petersen ◽  
Lennart J. Friis-Hansen ◽  
Andreas Kryger Jensen ◽  
Anders Nyboe Andersen ◽  
Ellen C.L. Løkkegaard
Keyword(s):  
Pregnant Women ◽  
Early Pregnancy ◽  
Clinical Chemistry ◽  
Clinical Care ◽  
Local Population ◽  
First Trimester ◽  
Reference Intervals ◽  
Specific Reference ◽  
Cancer Antigen 125 ◽  
Serum Samples

Abstract Background Pregnancy introduces major physiological changes that also alter biochemical analytes. Maternal and perinatal health can be optimized by early intervention and therefore, pregnancy-specific reference intervals (RIs) for the local population are warranted. While the second and third trimester-specific changes are well described, the first trimester is less well characterized. We therefore wanted to facilitate early detection of abnormalities by generating first trimester reference values for 29 common analytes. Methods In a prospective early pregnancy (PEP) cohort (2016–2017), 203 pregnant women were recruited from 4 to 8 weeks’ gestation. Consecutive blood samples were drawn every 2 weeks until an ongoing second trimester pregnancy (n = 164) or a miscarriage (n = 39) occurred. After exclusion of women with complicated pregnancies or deliveries (n = 42), 122 women were included. The serum samples collected at <6, 6–8, 8–10, 10–12 and >12 weeks’ gestation were analyzed for 29 common analytes. Subsequently the RIs were calculated according to the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) recommendations (2.5–97.5th percentiles) and compared with the conventional RIs for non-pregnant women. Results Human chorionic gonadotropin (hCG), progesterone (P4), estradiol (E2), pregnancy-associated plasma protein A (PAPP-A), cancer antigen 125 (CA125), thyroid stimulating hormone (TSH), creatinine (CREA) and albumin (ALB) showed an early pregnancy-dependent change compared with conventional limits. For ALB the change was seen at 5.5 weeks’ gestation. Conclusions We report gestational age-specific RIs available from the early part of the first trimester applicable to everyday clinical care of pregnant women. Well-known alterations of RIs seen in later trimesters are also observed in the first.

Gestation specific reference intervals for thyroid function tests in pregnancy

2016 ◽  
Vol 54 (8) ◽  
Author(s):  
Süleyman Akarsu ◽  
Filiz Akbiyik ◽  
Eda Karaismailoglu ◽  
Zeliha Gunnur Dikmen
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
First Trimester ◽  
Reference Intervals ◽  
Specific Reference ◽  
Thyroid Function Tests ◽  
Second Trimester ◽  
Third Trimester ◽  
The Third ◽  
Function Tests

AbstractThyroid function tests are frequently assessed during pregnancy to evaluate thyroid dysfunction or to monitor pre-existing thyroid disease. However, using non-pregnant reference intervals can lead to misclassification. International guidelines recommended that institutions should calculate their own pregnancy-specific reference intervals for free thyroxine (FT4), free triiodothyronine (FT3) and thyroid-stimulating hormone (TSH). The objective of this study is to establish gestation-specific reference intervals (GRIs) for thyroid function tests in pregnant Turkish women and to compare these with the age-matched non-pregnant women.Serum samples were collected from 220 non-pregnant women (age: 18–48), and 2460 pregnant women (age: 18–45) with 945 (39%) in the first trimester, 1120 (45%) in the second trimester, and 395 (16%) in the third trimester. TSH, FT4 and FT3 were measured using the Abbott Architect i2000SR analyzer.GRIs of TSH, FT4 and FT3 for first trimester pregnancies were 0.49–2.33 mIU/L, 10.30–18.11 pmol/L and 3.80–5.81 pmol/L, respectively. GRIs for second trimester pregnancies were 0.51–3.44 mIU/L, 10.30–18.15 pmol/L and 3.69–5.90 pmol/L. GRIs for third trimester pregnancies were 0.58–4.31 mIU/L, 10.30–17.89 pmol/L and 3.67–5.81 pmol/L. GRIs for TSH, FT4 and FT3 were different from non-pregnant normal reference intervals.TSH levels showed an increasing trend from the first trimester to the third trimester, whereas both FT4 and FT3 levels were uniform throughout gestation. GRIs may help in the diagnosis and appropriate management of thyroid dysfunction during pregnancy which will prevent both maternal and fetal complications.

Establishment of Reference Intervals for Alkaline Phosphatase in Pakistani Children Using a Data Mining Approach

2019 ◽  
Vol 51 (5) ◽  
pp. 484-490 ◽  
Author(s):  
Sibtain Ahmed ◽  
Jakob Zierk ◽  
Aysha Habib Khan
Keyword(s):  
Data Mining ◽  
Alkaline Phosphatase ◽  
Clinical Decision Making ◽  
Clinical Chemistry ◽  
Age Groups ◽  
Clinical Decision ◽  
German Society ◽  
Reference Intervals ◽  
Photometric Method ◽  
Data Mining Approach

Abstract Objective To establish reference intervals (RIs) for alkaline phosphatase (ALP) levels in Pakistani children using an indirect data mining approach. Methods ALP levels analyzed on a Siemens Advia 1800 analyzer using the International Federation of Clinical Chemistry’s photometric method for both inpatients and outpatients aged 1 to 17 years between January 2013 and December 2017, including patients from intensive care units and specialty units, were retrieved. RIs were calculated using a previously validated indirect algorithm developed by the German Society of Clinical Chemistry and Laboratory Medicine’s Working Group on Guide Limits. Results From a total of 108,845 results, after the exclusion of patients with multiple specimens, RIs were calculated for 24,628 males and 18,083 females with stratification into fine-grained age groups. These RIs demonstrate the complex age- and sex-related ALP dynamics occurring during physiological development. Conclusion The population-specific RIs serve to allow an accurate understanding of the fluctuations in analyte activity with increasing age and to support clinical decision making.

scholarly journals Analytical quality assessment and method comparison of immunoassays for the measurement of serum cobalamin and folate in dogs and cats

2019 ◽  
Vol 31 (2) ◽  
pp. 164-174 ◽  
Author(s):  
Susan A. McLeish ◽  
Kay Burt ◽  
Kostas Papasouliotis
Keyword(s):  
Method Comparison ◽  
Reference Intervals ◽  
Specific Reference ◽  
Altman Analysis ◽  
Poor Agreement ◽  
Bland Altman Analysis ◽  
Intestinal Dysbiosis ◽  
Deming Regression ◽  
Small Intestinal ◽  
Very High

Serum cobalamin and folate are often measured in cats and dogs as part of laboratory testing for intestinal disease, small intestinal dysbiosis, or exocrine pancreatic deficiency. We performed an analytical validation of human immunoassays for cobalamin and folate measurement (AIA-900 analyzer, Tosoh Bioscience) and compared results with those obtained using chemiluminescence assays (Immulite 2000 analyzer, Siemens Medical Solutions Diagnostics). Accuracy, precision, total observable error (TEobs%), and σ values were calculated for the immunoassays. Correlation and agreement were evaluated with Deming regression, Passing–Bablok regression, and Bland–Altman analysis. Cobalamin intra-assay and inter-assay CVs were 1.8–9.3% and 2.6–6.8%, respectively. Folate intra-assay and inter-assay CVs were 1.5–9.1% and 3.4–8.1%, respectively. TEobs (%) were ≤19 and ≤31 for cobalamin and folate, respectively. Sigma values were 3.60–11.50 for cobalamin and 2.90–7.50 for folate. Regression analysis demonstrated very high or high correlations for cobalamin [ r = 0.98 (dogs), 0.97 (cats)] and folate [ r = 0.88 (dogs), 0.92 (cats)] but Bland–Altman analysis revealed poor agreement for both. The immunoassays had good analytical performance for measuring cobalamin and folate in both species. Results obtained by the 2 analyzers cannot be used interchangeably and should be interpreted using instrument-specific reference intervals. Further studies are required to establish immunoassay-specific reference intervals and to evaluate the diagnostic performance and clinical utility of the analyzer for these analytes.

scholarly journals First- and Second-Trimester Reference Intervals for Thyroid Hormones during Pregnancy in “Rhea” Mother-Child Cohort, Crete, Greece

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Polyxeni Karakosta ◽  
Leda Chatzi ◽  
Emmanouil Bagkeris ◽  
Vasiliki Daraki ◽  
Dimitris Alegakis ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Reference Interval ◽  
Reference Intervals ◽  
Thyroid Stimulating Hormone ◽  
Specific Reference ◽  
Reference Ranges ◽  
Thyroid Function Tests ◽  
Second Trimester ◽  
Free Triiodothyronine ◽  
Reference Limit

Estimation and interpretation of thyroid function tests in pregnant women is of utmost importance for maternal, fetal and neonatal health. Our objective was to calculate laboratory- and geography-specific reference intervals for thyroid hormones during pregnancy in an iodine-sufficient area of the Mediterranean, Crete, Greece. This project was performed in the context of “Rhea” mother-child cohort. Fulfillment of extensive questionnaires and estimation of free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH), and antithyroid antibodies were performed. The reference population was defined using inclusion criteria regarding thyroidal, obstetric, and general medical status of women. Reference interval for TSH was 0.05–2.53 μIU/mL for the first and 0.18–2.73 μIU/mL for the second trimester. 6,8% and 5,9% of women in the first and second trimester, respectively, had TSH higher than the upper reference limit. These trimester-specific population-based reference ranges are essential in everyday clinical practice for the correct interpretation of thyroid hormone values and accurate classification of thyroid disorders.

scholarly journals Evaluation of maternal thyroid function during pregnancy: the importance of using gestational age-specific reference intervals

2007 ◽  
Vol 157 (4) ◽  
pp. 509-514 ◽  
Author(s):  
Rt Stricker ◽  
M Echenard ◽  
R Eberhart ◽  
M-C Chevailler ◽  
V Perez ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Thyroid Function ◽  
Gestational Age ◽  
Thyroid Disease ◽  
Thyroid Dysfunction ◽  
Reference Intervals ◽  
Specific Reference ◽  
Thyroid Function Tests ◽  
Laboratory Evidence ◽  
Maternal Thyroid

Background: Maternal thyroid dysfunction has been associated with a variety of adverse pregnancy outcomes. Laboratory measurement of thyroid function plays an important role in the assessment of maternal thyroid health. However, occult thyroid disease and physiologic changes associated with pregnancy can complicate interpretation of maternal thyroid function tests (TFTs). Objective and methods: To 1) establish the prevalence of laboratory evidence for autoimmune thyroid disease (AITD) in pregnant women; 2) establish gestational age-specific reference intervals for TFTs in women without AITD; and 3) examine the influence of reference intervals on the interpretation of TFT in pregnant women. Serum samples were collected from 2272 pregnant women, and TFT performed. Gestational age-specific reference intervals were determined in women without AITD, and then compared with the non-pregnant assay-specific reference intervals for interpretation of testing results. Results: Thyroid peroxidase antibodies (TPO-Ab) and thyroglobulin antibodies (Tg-Ab) were positive in 10.4 and 15.7% of women respectively. TPO-Ab level was related to maternal age, but TPO-Ab status, Tg-Ab status, and Tg-Ab level were not. Women with TSH > 3.0 mIU/l were significantly more likely to be TPO-Ab positive. Gestational age-specific reference intervals for TFT were significantly different from non-pregnant normal reference intervals. Interpretation of TFT in pregnant women using non-pregnant reference intervals could potentially result in misclassification of a significant percentage of results (range: 5.6–18.3%). Conclusion: Laboratory evidence for thyroid dysfunction was common in this population of pregnant women. Accurate classification of TFT in pregnant women requires the use of gestational age-specific reference intervals.

scholarly journals Reference intervals for 24 laboratory parameters determined in 24-hour urine collections

2016 ◽  
Vol 54 (1) ◽  
Author(s):  
Raffaele Curcio ◽  
Helen Stettler ◽  
Paolo M. Suter ◽  
Jasmin Barman Aksözen ◽  
Lanja Saleh ◽  
...  
Keyword(s):  
Clinical Chemistry ◽  
Large Population ◽  
Population Based ◽  
Reference Intervals ◽  
Specific Reference ◽  
Urine Excretion ◽  
Sodium Potassium ◽  
Men And Women ◽  
Laboratory Parameters ◽  
Urine Cortisol

AbstractReference intervals for many laboratory parameters determined in 24-h urine collections are either not publicly available or based on small numbers, not sex specific or not from a representative sample.Osmolality and concentrations or enzymatic activities of sodium, potassium, chloride, glucose, creatinine, citrate, cortisol, pancreatic α-amylase, total protein, albumin, transferrin, immunoglobulin G, αBy contrast to most published reference intervals, which do not stratify for sex, reference intervals of 12 of 24 laboratory parameters in 24-h urine collections and of eight of 16 parameters as creatinine-normalized ratios differed significantly between men and women. For six parameters calculated as 24-h urine excretion and four parameters calculated as creatinine-normalized ratios no reference intervals had been published before. For some parameters we found significant and relevant deviations from previously reported reference intervals, most notably for 24-h urine cortisol in women. Ten 24-h urine parameters showed weak or moderate sex-specific correlations with age.By applying up-to-date analytical methods and clinical chemistry analyzers to 24-h urine collections from a large population-based cohort we provide as yet the most comprehensive set of sex-specific reference intervals calculated according to CLSI guidelines for parameters determined in 24-h urine collections.

scholarly journals Establishment of dry chemistry based reference intervals of renal function test parameters for the adult population of Kaski District, Nepal

2021 ◽  
Author(s):  
Goma Kathayat ◽  
Daya Ram Pokharel ◽  
Naval Kishor Yadav ◽  
Manoj Sigdel
Keyword(s):  
Renal Function ◽  
Clinical Chemistry ◽  
Adult Population ◽  
Clinical Decision ◽  
Cross Sectional Study ◽  
Reference Intervals ◽  
Cross Sectional ◽  
Renal Function Test ◽  
Test Parameters ◽  
Function Test

Abstract BackgroundReference intervals (RI) for clinical chemistry test parameters are specific to the method of measurement and population under service. However, there have been no locally available dry chemistry based RIs for the Nepalese population. Thus, the present study aimed to establish dry chemistry based RIs for sodium, potassium, urea, and creatinine specific to adult populations of Kaski districts, Nepal.MethodsThis was a cross-sectional study conducted at the Manipal Teaching Hospital, Pokhara, Kaski, Nepal on 360 healthy adult participants aged 18-65 years. The test parameters under study were analyzed using a fully automated OCD Vitros 350 dry chemistry analyzer following the protocols provided by the reagent kit manufacturer. The RIs were estimated using reference limits at 2.5th and 97.5th percentiles. The normal distribution of the data was tested by Kolmogorov–Smirnov, and Shapiro–Wilk tests. The differences between males and females RIs were compared by the Mann-Whitney test while age-specific RI for each gender was compared by One-Way-ANOVA and Dunnett's Multiple Comparisons Tests. All the data were managed and analyzed using MS Excel and SPSS version 20.ResultsThe RIs of urea, creatinine, sodium and potassium specific to the adult population of Kaski district, Nepal are as follows: urea: 11.89-37.81 mg/dL (males: 13.09-38.40; females: 11.80-36.20); creatinine: 0.50-1.20 mg/dL (males: 0.55-1.20; females: 0.40-0.90); sodium 135-146 mEq/L (males: 135-146; females: 135-146) and potassium 3.60-5.10 mEq/L (males: 3.54-5.0; females: 3.60-5.10). These RIs were found to be different from currently used RIs provided by the reagent manufacturer. RIs of all the test parameters were significantly influenced by the age of the study participants. However, only the RIs of urea, creatinine, and potassium were significantly influenced by gender.Conclusions The present study has for the first time established dry chemistry based RI for selected renal function test parameters specific to the adult population of Kaski district, Nepal. This result will aid the clinician in minimizing the errors in result interpretation and making a precise clinical decision.

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