scholarly journals Thyroxine, thyrotropin, and age in a euthyroid hospital patient population

1997 ◽  
Vol 43 (11) ◽  
pp. 2143-2148 ◽  
Author(s):  
Richard Davey
Keyword(s):  
Thyroid Disease ◽  
Clinical Condition ◽  
Patient Population ◽  
Reference Intervals ◽  
Hospital Patient ◽  
Free T4 ◽  
Diagnostic Algorithms ◽  
Age Related ◽  
Range Of Variation

Abstract The diagnosis of thyroid disease now often can be achieved reliably by measuring thyrotropin (TSH) alone. Thyroxine (T4), triiodothyronine, and other analytes are only needed if TSH and the accompanying clinical condition are discordant. We describe here work that confirms the age independence of TSH in both inpatient and outpatient euthyroid hospital populations between ages 20 and at least 80 years, and demonstrates that although free T4 does vary with age, the range of variation remains within the T4reference interval. On this basis, TSH-based thyroid diagnostic algorithms can be used reliably in adults without reference to age-related reference intervals.

scholarly journals Guidelines for diagnosis and monitoring of thyroid disease: nonthyroidal illness

1996 ◽  
Vol 42 (1) ◽  
pp. 188-192 ◽  
Author(s):  
J R Stockigt
Keyword(s):  
Positive Predictive Value ◽  
Clinical Features ◽  
Thyroid Function ◽  
Predictive Value ◽  
Thyroid Disease ◽  
Thyroid Dysfunction ◽  
Reference Intervals ◽  
Free T4 ◽  
Prognostic Information ◽  
Increased Risk

Abstract On the basis of low specificity, poor positive predictive value, and cost, there is at present no basis for routine assessment of thyroid function in acutely hospitalized patients, unless clinical features suggest the possibility of thyroid dysfunction, or a patient's background increases the likelihood of thyroid dysfunction. When used in severely ill patients, estimates of both thyroxine (T4) and thyrotropin (TSH) show a high prevalence of abnormal results, but lack specificity and have poor positive predictive value for true thyroid disease. When thyroid function is tested in the critically ill, the positive predictive value for true thyroid disease of both free T4 and TSH measurements could be improved by using wider reference intervals than for unselected populations. The knowledge of nonspecific disease-related abnormalities of triiodothyronine, T4, and TSH is not currently likely to yield useful prognostic information or to alter management for individual patients. Thyroid testing should be readily available for any acutely ill patient with any clinical features that suggest thyroid dysfunction, and for groups at increased risk of thyroid dysfunction. An initial abnormal result for either TSH or free T4 estimate should be followed by combined analysis of free T4 and TSH with the best available methodology. Diagnosis of thyroid dysfunction should be based on the T4-TSH relation rather than either value alone. Persistence of an apparent diagnostic abnormality should be confirmed before therapy is commenced.

scholarly journals Reference intervals for 26 common biochemical analytes in term neonates in Jilin Province, China

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kaijin Wang ◽  
Xuetong Zhu ◽  
Qi Zhou ◽  
Jiancheng Xu
Keyword(s):  
Lactate Dehydrogenase ◽  
Clinical Decision Making ◽  
Reference Intervals ◽  
Individual Characteristics ◽  
Integrated System ◽  
Delivery Mode ◽  
Related Factor ◽  
Term Neonates ◽  
Age Related ◽  
Laboratory Test Results

Abstract Background Biochemical analytes provide information for neonatal disease management and therapy, and population-based reference intervals (RIs) are essential to accurately interpret laboratory test results. This study aimed to establish local RIs for biochemical assays in term neonates. Methods A total of 195 healthy term neonates from birth to 3rd day were recruited as reference individuals prospectively. Analytes of 26 common biochemistries were measured using the VITROS 5600 Integrated System. The 3-level nested ANOVA was performed to assess the need for partitioning RIs of each analyte, and RIs were derived by a nonparametric method or robust method. Multiple regression analysis was used to evaluate specific correlations between the analytes and individual characteristics including age, gender, gestational age, birthweight and delivery mode. Results There were no between-sex differences in all analytes, whereas there were significant between-day-age differences in 6 analytes. Small between-delivery-mode differences were observed in the results for potassium, phosphorus, and urea. The major related factor of most analytes was postnatal age. During the first 3 days, values of iron, lipids and lipoproteins increased; creatinine, urea, uric acid, creatine kinase and lactate dehydrogenase decreased; other analytes showed slight changes or relatively stable trends. Reference limits of some analytes, particularly lactate dehydrogenase and alkaline phosphatase, were significantly different from adult and pediatric groups. Conclusions RIs of 26 common biochemical analytes are established for term neonates aged 0 to 3 days in northeast China. Additionally, it is suggested that age-related changes should be valued in the clinical decision-making process for newborns.

scholarly journals Experience with the Urinary Tetrasaccharide Metabolite for Pompe Disease in the Diagnostic Laboratory

Metabolites ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 446
Author(s):  
Jennifer T. Saville ◽  
Maria Fuller
Keyword(s):  
Pompe Disease ◽  
Late Onset ◽  
Reference Interval ◽  
Laboratory Diagnosis ◽  
Reference Intervals ◽  
Confirmatory Test ◽  
Diagnostic Laboratory ◽  
Age Related ◽  
Initial Drop ◽  
Monitoring Treatment

Following clinical indications, the laboratory diagnosis of the inherited metabolic myopathy, Pompe disease (PD), typically begins with demonstrating a reduction in acid alpha-glucosidase (GAA), the enzyme required for lysosomal glycogen degradation. Although simple in concept, a major challenge is defining reference intervals, as even carriers can have reduced GAA, and pseudodeficiencies complicate interpretation. Here, we developed a mass spectrometric assay for quantification of a urinary glycogen metabolite (tetrasaccharide) and reported on its utility as a confirmatory test for PD in a diagnostic laboratory. Using two age-related reference intervals, eight returned tetrasaccharide concentrations above the calculated reference interval but did not have PD, highlighting non-specificity. However, retrospective analysis revealed elevated tetrasaccharide in seven infantile-onset (IOPD) cases and sixteen late-onset (LOPD) cases, and normal concentrations in one heterozygote. Prospective tetrasaccharide analysis in nine individuals with reduced GAA confirmed IOPD in one, LOPD in six and identified two heterozygotes. Using this metabolite as a biomarker of therapeutic response was not overly informative; although most patients showed an initial drop following therapy initiation, tetrasaccharide concentrations fluctuated considerably and remained above reference intervals in all patients. While useful as a confirmation of PD, its utility as a biomarker for monitoring treatment warrants further investigation.

Cognitive Frailty: A Systematic Review of Epidemiological and Neurobiological Evidence of an Age-Related Clinical Condition

2015 ◽  
Vol 18 (5) ◽  
pp. 389-412 ◽  
Author(s):  
Francesco Panza ◽  
Vincenzo Solfrizzi ◽  
Maria Rosaria Barulli ◽  
Andrea Santamato ◽  
Davide Seripa ◽  
...  
Keyword(s):  
Systematic Review ◽  
Clinical Condition ◽  
Cognitive Frailty ◽  
Age Related

scholarly journals Impact of age, body weight and metabolic risk factors on steroid reference intervals in men

2020 ◽  
Vol 182 (5) ◽  
pp. 459-471
Author(s):  
Marco Mezzullo ◽  
Guido Di Dalmazi ◽  
Alessia Fazzini ◽  
Margherita Baccini ◽  
Andrea Repaci ◽  
...  
Keyword(s):  
Risk Factors ◽  
Reference Intervals ◽  
Metabolic Risk Factors ◽  
Specific Reference ◽  
Metabolic Risk ◽  
Cross Sectional ◽  
Cholesterol Ratio ◽  
Age Related ◽  
Reference Limits ◽  
17 Hydroxyprogesterone

Objective To evaluate the independent impact of age, obesity and metabolic risk factors on 13 circulating steroid levels; to generate reference intervals for adult men. Design Cross-sectional study. Methods Three hundred and fifteen adults, drug-free and apparently healthy men underwent clinical and biochemical evaluation. Thirteen steroids were measured by LC-MS/MS and compared among men with increasing BMI. Moreover, the independent impact of age, BMI and metabolic parameters on steroid levels was estimated. Upper and lower reference limits were generated in steroid-specific reference sub-cohorts and compared with dysmetabolic sub-cohorts. Results We observed lower steroid precursors and testosterone and increase in estrone levels in men with higher BMI ranges. By multivariate analysis, 17-hydroxyprogesterone and dihydrotestosterone decreased with BMI, while cortisol decreased with waist circumference. Estrone increased with BMI and systolic blood pressure. Testosterone decreased with worsening insulin resistance. 17-hydroxypregnenolone and corticosterone decreased with increasing total/HDL-cholesterol ratio. Age-related reference intervals were estimated for 17-hydroxypregnenolone, DHEA, 17-hydroxyprogesterone, corticosterone, 11-deoxycortisol, cortisol and androstenedione, while age-independent reference intervals were estimated for progesterone, 11-deoxycorticosterone, testosterone, dihydrotestosterone, estrone and estradiol. Testosterone lower limit was 2.29 nmol/L lower (P = 0.007) in insulin resistant vs insulin sensitive men. Furthermore, the upper limits for dihydrotestosterone (−0.34 nmol/L, P = 0.045), cortisol (−87 nmol/L, P = 0.045–0.002) and corticosterone (−10.1 nmol/L, P = 0.048–0.016) were lower in overweight/obese, in abdominal obese and in dyslipidaemic subjects compared to reference sub-cohorts, respectively. Conclusions Obesity and mild unmedicated metabolic risk factors alter the circulating steroid profile and bias the estimation of reference limits for testosterone, dihydrotestosterone, cortisol and corticosterone. Applying age-dependent reference intervals is mandatory for steroid precursors and corticosteroids.

scholarly journals TSH enhancement of FT4 to FT3 conversion is age dependent

2016 ◽  
Vol 175 (1) ◽  
pp. 49-54 ◽  
Author(s):  
David Strich ◽  
Gilad Karavani ◽  
Shalom Edri ◽  
David Gillis
Keyword(s):  
Age Groups ◽  
Thyroid Stimulating Hormone ◽  
Older Age ◽  
Age Group ◽  
Free T4 ◽  
Free T3 ◽  
Age Related ◽  
Differential Increase ◽  
Retrospective Examination ◽  
Tsh Levels

ObjectiveWe previously reported increasing free T3 (FT3) to free T4 (FT4) ratios as thyroid-stimulating hormone (TSH) increases within the normal range in children. It is not known if this phenomenon is age-related among humans, as previously reported in rats. This study examines the relationships between TSH and FT3/FT4 ratios in different ages.DesignRetrospective examination of thyroid tests from patients without thyroid disease from community clinics.MethodsFree T3, free T4, and TSH levels from 527 564 sera collected from patients aged 1 year or greater were studied. Exclusion criteria were the following: missing data, TSH greater than 7.5mIU/L, and medications that may interfere with thyroid hormone activity. A total of 27 940 samples remaining after exclusion were stratified by age. Samples with available anthropometric data were additionally stratified for body mass index (BMI). Correlations of TSH to FT4, FT3, and FT3/FT4 ratios by age group were examined.ResultsUp to age 40, for each increasing TSH quartile, FT3 and the FT3/FT4 ratio increased and FT4 decreased significantly (for both FT3, FT4 and FT3/FT4 ratio,P<0.05 for every TSH quartile when compared with the 1st quartile, except FT3 in the 30–40 age group). In older age groups, increasing TSH was not associated with increased FT3/FT4 ratio.ConclusionAs TSH levels increase, FT3/FT4 ratios increase until age 40, but this differential increase does not occur in older age groups. This may reflect a decrease in thyroxine (T4) to triiodothyronine (T3) conversion with age, which may be part of the aging process.

Age-related changes and reference intervals of RANKL, OPG, and bone turnover markers in Indian women

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Sandhya Nair ◽  
Sonam Hatkar ◽  
Anushree Patil ◽  
Suchitra Surve ◽  
Beena Joshi ◽  
...  
Keyword(s):  
Bone Turnover ◽  
Bone Turnover Markers ◽  
Reference Intervals ◽  
Indian Women ◽  
Age Related ◽  
Turnover Markers ◽  
Age Related Changes

Free thyroxin by radioimmunoassay: evaluation of a new direct method involving a radiolabeled thyroxin analog.

1983 ◽  
Vol 29 (10) ◽  
pp. 1781-1786 ◽  
Author(s):  
N P Kubasik ◽  
P A Lundberg ◽  
R G Brodows ◽  
G D Hallauer ◽  
D G Same ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Oral Contraceptives ◽  
Thyroid Disease ◽  
Direct Method ◽  
Age Effect ◽  
Free T4 ◽  
Nonthyroidal Illness ◽  
Serum Free ◽  
Normal Individuals ◽  
The Mean

Abstract We present here the first performance evaluation of a new direct method for free thyroxin (T4) in serum by radioimmunoassay, with use of coated tubes and a radiolabeled T4 analog (Diagnostic Products Corp.). The assay is precise and robust: within-run imprecision (CV), 3.1-6.6%; between-run imprecision, 4.0-7.9%; no demonstrable variation between technologists irrespective of experience with the method. No outliers were observed when we compared the free T4 results with serum total T4. Reference values are reported for a total of 1243 euthyroid subjects; there was no significant age effect on serum free T4 in women 26 to 72 years old. The biological variation was about +/- 35% of the mean (2 SD). Free T4 results are the same for serum and plasma. The assay performs well in hypothyroidism and hyperthyroidism, and distinguishes individuals with thyroid disease from normal individuals. Free T4 values in women taking oral contraceptives are normal. Depressed results were often observed in acute nonthyroidal illness and continuing pregnancy. These results were directly comparable with those of another commercial direct radiolabeled-T4 analog kit for free T4.

scholarly journals Establishment of variation source and age-related reference interval models for 22 common biochemical analytes in older people using real-world big data mining

2020 ◽  
Vol 49 (6) ◽  
pp. 1062-1070
Author(s):  
Chaochao Ma ◽  
Liangyu Xia ◽  
Xinqi Chen ◽  
Jie Wu ◽  
Yicong Yin ◽  
...  
Keyword(s):  
Big Data ◽  
Older People ◽  
Real World ◽  
Reference Interval ◽  
Reference Intervals ◽  
Ageing Population ◽  
Factors Affecting ◽  
Age Related ◽  
The Status ◽  
Source Models

Abstract Background the ageing population has increased in many countries, including China. However, reference intervals (RIs) for older people are rarely established because of difficulties in selecting reference individuals. Here, we aimed to analyse the factors affecting biochemical analytes and establish RI and age-related RI models for biochemical analytes through mining real-world big data. Methods data for 97,220 individuals downloaded from electronic health records were included. Three derived databases were established. The first database included 97,220 individuals and was used to build age-related RI models after identifying outliers by the Tukey method. The second database consisted of older people and was used to establish variation source models and RIs for biochemical analytes. Differences between older and younger people were compared using the third database. Results sex was the main source of variation of biochemical analytes for older people in the variation source models. The distributions of creatinine and uric acid were significantly different in the RIs of biochemical analytes for older people established according to sex. Age-related RI models for biochemical analytes that were most affected by age were built and visualized, revealing various patterns of changes from the younger to older people. Conclusion the study analysed the factors affecting biochemical analytes in older people. Moreover, RI and age-related RI models of biochemical analytes for older people were established to provide important insight into biological processes and to assist clinical use of various biochemical analytes to monitor the status of various diseases for older people.

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