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.

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.

scholarly journals SUN-222 Pre- and Post-Pubertal Reference Ranges for Oxygenated Androgens in Saliva

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Joanne Adaway ◽  
Graeme Eisenhofer ◽  
Angela Huebner ◽  
Nils Krone ◽  
Malcolm McTaggart ◽  
...  
Keyword(s):  
Reference Interval ◽  
Reference Intervals ◽  
Range Data ◽  
Reference Ranges ◽  
Non Invasive ◽  
Premature Adrenarche ◽  
Upper Limits ◽  
Males And Females ◽  
Monitoring Treatment ◽  
Ovarian Syndrome

Abstract Oxygenated androgens such as 11 β-hydroxyandrostenedione (11OHA4) and 11-ketotestosterone (11KT) contribute significantly to the androgen pool in humans and their measurement has been shown to be useful in diagnosing disorders such as polycystic ovarian syndrome or premature adrenarche and also in monitoring treatment of congenital adrenal hyperplasia, alongside the classical androgens. Their measurement in saliva is particularly advantageous due to the non-invasive nature of sampling, meaning samples can easily be taken regularly to monitor treatment; however reference range data is not currently available for 11OHA4 and 11KT, limiting their clinical use. These analytes were measured in saliva samples from pre and post-pubertal males and females to inform reference ranges for these analytes. Samples collected into salivettes as part of the PRIMMS study (Technische Universität Dresden) were used for this work. A total of 130 samples (35 from pre-pubertal females, 43 from post-pubertal females, 42 from pre-pubertal males and 20 from post-pubertal males) were analysed for 11OHA4 and 11KT by LC-MS/MS. The ages of the participants ranged from 3.77 to 14.0 years in the pre-pubertal samples and 13.9-17.9 years in the post-pubertal samples. Pubertal status was determined clinically. The upper cut-off of the reference interval for 11OHA4 was 560 pmol/L in pre-pubertal females and 590 pmol/L in males, whilst 11KT had an upper limit of 216 pmol/L in females and 205 pmol/L in males. The upper limits of the ranges were higher in post-pubertal samples, with ranges of up to 1542 pmol/L in females and 1775 pmol/L in males for 11OHA4; the ranges for 11KT were up to 654 pmol/L for post pubertal females and 585 pmol/L for post-pubertal males. The data shows, as expected, a rise in the 11 oxygenated androgens post puberty. The upper limits of reference intervals for both analytes were very similar in males and females both pre- and post pubertally. These data can be used to inform clinical interpretation of the 11-oxygenated androgens; further work is required with larger cohorts of samples to develop more robust reference ranges.

scholarly journals Combination of Culture, Antigen and Toxin Detection, and Cytotoxin Neutralization Assay for OptimalClostridium difficileDiagnostic Testing

2013 ◽  
Vol 24 (2) ◽  
pp. 89-92 ◽  
Author(s):  
Michelle J Alfa ◽  
Shadi Sepehri
Keyword(s):  
Diagnostic Algorithm ◽  
Laboratory Diagnosis ◽  
Neutralization Assay ◽  
Confirmatory Test ◽  
Toxin A ◽  
Diagnostic Laboratory ◽  
Toxigenic Culture ◽  
Stool Samples ◽  
Step Algorithm ◽  
One Year

BACKGROUND: There has been a growing interest in developing an appropriate laboratory diagnostic algorithm forClostridium difficile, mainly as a result of increases in both the number and severity of cases ofC difficileinfection in the past decade. AC difficilediagnostic algorithm is necessary because diagnostic kits, mostly for the detection of toxins A and B or glutamate dehydrogenase (GDH) antigen, are not sufficient as stand-alone assays for optimal diagnosis ofC difficileinfection. In addition, conventional reference methods forC difficiledetection (eg, toxigenic culture and cytotoxin neutralization [CTN] assays) are not routinely practiced in diagnostic laboratory settings.OBJECTIVE: To review the four-step algorithm used at Diagnostic Services of Manitoba sites for the laboratory diagnosis of toxigenicC difficile.RESULT: One year of retrospectiveC difficiledata using the proposed algorithm was reported. Of 5695 stool samples tested, 9.1% (n=517) had toxigenicC difficile. Sixty per cent (310 of 517) of toxigenicC difficilestools were detected following the first two steps of the algorithm. CTN confirmation of GDH-positive, toxin A- and B-negative assays resulted in detection of an additional 37.7% (198 of 517) of toxigenicC difficile. Culture of the third specimen, from patients who had two previous negative specimens, detected an additional 2.32% (12 of 517) of toxigenicC difficilesamples.DISCUSSION: Using GDH antigen as the screening and toxin A and B as confirmatory test forC difficile, 85% of specimens were reported negative or positive within 4 h. Without CTN confirmation for GDH antigen and toxin A and B discordant results, 37% (195 of 517) of toxigenicC difficilestools would have been missed. Following the algorithm, culture was needed for only 2.72% of all specimens submitted forC difficiletesting.CONCLUSION: The overview of the data illustrated the significance of each stage of this four-stepC difficilealgorithm and emphasized the value of using CTN assay and culture as parts of an algorithm that ensures accurate diagnosis of toxigenicC difficile.

The decision-making levels of urine tetrasaccharide for the diagnosis of Pompe disease in the Turkish population

2020 ◽  
Vol 33 (3) ◽  
pp. 391-395 ◽  
Author(s):  
Erhan Canbay ◽  
Melisa Vural ◽  
Sema Kalkan Uçar ◽  
Ebru Demirel Sezer ◽  
Hatice Karasoy ◽  
...  
Keyword(s):  
Decision Making ◽  
Pompe Disease ◽  
High Performance ◽  
Late Onset ◽  
Turkish Population ◽  
Reference Intervals ◽  
Healthy Controls ◽  
Age Group ◽  
Healthy Individuals ◽  
First Year Of Life

AbstractBackgroundRecently, urinary excretion of the tetrasaccharide 6-α-D-glucopyranosyl-maltotriose (Glc4) has been proposed as a marker for the diagnosis and monitoring of Pompe disease (PD). We aimed to determine the reference intervals and reliable decision-making levels of urine tetrasaccharide concentrations for the diagnosis of infantile- and late-onset Pompe patients in the Turkish population.MethodsIn this study, nine patients with PD (five of them with late-onset PD [LOPD]) and 226 healthy individuals (aged 0–64 years) were included. Urine Glc4 concentrations were determined using the ultra-high-performance liquid chromatography (UHPLC) tandem mass spectrometry (MS/MS) method.ResultsOur data showed that the urine tetrasaccharide levels decreased with age in healthy individuals (p < 0.001, r = −0.256). It was higher especially during the first year of life compared to that in the elder subjects. The tetrasaccharide level of Pompe patients was higher compared to that of healthy controls of the same age: 99 ± 68 mmol/mol creatinine for infantile onset vs. 4.0 ± 3.0 mmol/mol creatinine for healthy controls of the same age group and 12.1 ± 17.4 mmol/mol creatinine for late onset vs. 1.7±1.2 mmol/mol creatinine for healthy controls of the same age group.ConclusionsThe results of this study showed that the reference intervals of tetrasaccharide in urine changed over time; therefore, it is critically important to define age-based decision levels for the diagnosis of LOPD.

Albumin and calcium reference interval using healthy individuals and a data-mining approach

2020 ◽  
Vol 57 (5) ◽  
pp. 373-381 ◽  
Author(s):  
N Jassam ◽  
A Luvai ◽  
D Narayanan ◽  
D Turnock ◽  
G Lee ◽  
...  
Keyword(s):  
Metrological Traceability ◽  
Reference Interval ◽  
Reference Population ◽  
Reference Intervals ◽  
Healthy Individuals ◽  
Reference Limit ◽  
Common Reference ◽  
Age Related ◽  
Upper Reference Limit ◽  
Analytical Platforms

Background Harmonization of reference intervals for analytes that have a sound calibration and metrological traceability is a widely recommended practice. The UK Pathology Harmony has recently harmonized reference intervals for calcium and albumin. In this study, we have determined the reference intervals for calcium and albumin on the UK’s most commonly used analytical platforms. Method A prospective reference population of healthy individuals was recruited according to the IFCC CRIDL criteria. A second indirect population was collected from 14 primary care setting and measured in laboratories using various analytical platforms and methods (Roche, Abbott, Beckman and Siemens analytical platforms). Results In total, 299 subjects were recruited; the central 95th centile values for calcium for three out of four analytical platforms were in a close agreement with UK Pathology Harmony reference intervals of 2.2–2.6 mmol/L. Reference intervals of BCG methods from both cohorts and irrespective of analytical platforms were higher for both lower and upper reference limits than those for BCP. In comparison, the indirect study showed an age-related variation. The younger population reference intervals varied by up to 5.7% at the lower reference limit and up to 12% at the upper reference limit compared with Pathology Harmony reference intervals, and the older population showed a variation of up to 14% at both limits. Conclusion While calcium reference intervals can be a subject for harmonization, albumin reference intervals studied showed large variation which is unsupportive of embracing a common reference interval for albumin.

Normal reference interval for thyrotropin response to thyroliberin: dependence on age, sex, free thyroxin index, and basal concentrations of thyrotropin.

1984 ◽  
Vol 30 (2) ◽  
pp. 196-199 ◽  
Author(s):  
E M Erfurth ◽  
N E Nordén ◽  
P Hedner ◽  
A Nilsson ◽  
L Ek
Keyword(s):  
Linear Regression Analysis ◽  
Reference Interval ◽  
Multiple Linear Regression Analysis ◽  
Reference Intervals ◽  
Multivariate Statistical Methods ◽  
Individual Values ◽  
Multivariate Statistical ◽  
Normal Reference ◽  
Age Related ◽  
Basal Concentration

Abstract We measured the thyrotropin response (delta TSH) to 200 micrograms of thyroliberin in 131 subjects without thyroid dysfunction or other disease and with basal values for thyroid function that were within the normal reference intervals for our laboratory. By univariate and multivariate statistical methods we found delta TSH to be significantly influenced by the basal concentration of thyrotropin (TSH0) and the free thyroxin index (FT4I). When the effects of variations in TSH0 and FT4I were eliminated, delta TSH in men under 40 years of age did not differ from that in women. A decrease in delta TSH with increasing age was found in men but not in women. Thus a reference interval for delta TSH should consider TSH0, FT4I, and, in men, age. On the basis of multiple linear regression analysis, we constructed a formula for delta TSH reference intervals that takes into account individual values for TSH0 and FT4I. The formula should be applicable for women, regardless of age, up to 77 years and for men under 40 years. For older men a correction for the age-related decrease in delta TSH must be applied.

Age-related reference values for urinary excretion of sialic acid and deoxysialic acid: application to diagnosis of storage disorders of free sialic acid

1995 ◽  
Vol 41 (4) ◽  
pp. 544-547 ◽  
Author(s):  
J Romppanen ◽  
I Mononen
Keyword(s):  
Sialic Acid ◽  
Urinary Excretion ◽  
Reference Values ◽  
Reference Interval ◽  
Reference Intervals ◽  
Mean Value ◽  
Hplc Method ◽  
Age Related ◽  
Free Sialic Acid ◽  
Storage Disorders

Abstract We have established by HPLC age-related reference intervals for sialic acid urinary excretion in 364 control individuals to assist in evaluating the clinical significance of the free sialic acid concentration in urine. In addition, an HPLC method for quantitative analysis of free deoxysialic acid was developed, and age-related reference intervals for excretion of this compound in urine were established. In patients with storage disorders of free sialic acid (n = 11) the sialic acid excretion was increased 2- to 35-fold, compared with the mean value of the control subjects in the corresponding age group, and exceeded the interval in each case. The excretion of deoxysialic acid was within the reference interval in all of the patients, indicating that its metabolism was not affected in the disorders. The age-related reference values assist in evaluating the excretion of free sialic acid in the diagnosis of storage disorders of free sialic acid, especially in young children.

scholarly journals Nomogram of age-specific anti-Müllerian hormone levels in healthy Egyptian females

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254858
Author(s):  
Eman Ahmed El-Attar ◽  
Tamer A. Hosny ◽  
Kiyoshi Ichihara ◽  
Rania N. Bedair ◽  
Ahmed Salah El-Din Tork
Keyword(s):  
Reference Interval ◽  
Reference Intervals ◽  
Specific Reference ◽  
Clinical Settings ◽  
Power Transformation ◽  
Serum Samples ◽  
Female Age ◽  
Age Related ◽  
Age Dependent ◽  
Age Range

Background Anti-Müllerian hormone (AMH) is an important determinant of ovarian reserve in fertility workups in many clinical settings. Thus, we investigated the age dependent decline in AMH specific to the Egyptian population and sought to establish an age dependent reference interval parametrically. Methods Serum samples were collected from 841 apparently healthy women. AMH was measured using an electro-chemiluminescent technique. Box-Cox power transformation was used to make the AMH distribution Gaussian for parametric derivation of reference intervals. Results Power of 0.4 was found optimal for Gaussian transformation of AMH reference values. We demonstrate the strong negative relation between circulating AMH and female age with Spearman’s correlation coefficient of rS = −0.528. Age-specific reference interval was determined for every 5 years of age from 16 to 49, and nomogram was constructed by smoothing the lines connecting adjacent lower and upper reference limits. Conclusion The age-specific reference intervals and the age-AMH nomogram could be valuable in the clinical practice of in reproductive medicine. To our knowledge, this is the first study to confirm AMH levels in Egyptian females. We were able to explore age-related AMH levels specific to Egyptian females in the fertile age group and to treat skewed AMH data in a multi-step scheme using power transformation. Thus, a more accurate nomogram was constructed accommodating a profile delineated for a wide age range and a rescaled AMH axis improving its usability.

Difficulties in establishing reference intervals for special fluids: the example of 5-hydroxyindoleacetic acid and homovanillic acid in cerebrospinal fluids

2004 ◽  
Vol 42 (7) ◽  
Author(s):  
Jean-Louis Dhondt
Keyword(s):  
Cerebrospinal Fluid ◽  
Homovanillic Acid ◽  
Reference Interval ◽  
Reference Intervals ◽  
Control Group ◽  
Age Related ◽  
Wide Range ◽  
Hydroxyindoleacetic Acid ◽  
Biochemical Measurements

AbstractBiochemical measurements in “special fluids” are complicated with the problem of reference intervals. Reference intervals are difficult to establish for these types of samples since they are usually only collected in patients with clinical suspicion of disease. Determination of neurotransmitter metabolites in cerebrospinal fluid illustrates this difficulty. This paper will review the factors and circumstances that have been identified or are suspected to modifythe concentration of 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) in cerebrospinal fluid. In addition to obvious parameters such as age-related variation that can affect the concentration of 5-HIAA and HVA in cerebrospinal fluid, a varietyof other factors can explain the wide range of “control” group sizes reported in the literature. Reference intervals must take into account the purpose of cerebrospinal fluid examinations, whether they be prospective studies to explore physio-pathologic relationships or for diagnostic purposes. In the latter case, certain neurological disorders cannot be excluded if a single measured value is within the reference interval.

Determination of reference intervals for serum magnesium

1990 ◽  
Vol 36 (5) ◽  
pp. 756-758 ◽  
Author(s):  
G O Duncanson ◽  
H G Worth
Keyword(s):  
Alkaline Phosphatase ◽  
Gaussian Distribution ◽  
Parametric Analysis ◽  
Serum Magnesium ◽  
Reference Interval ◽  
Reference Intervals ◽  
Age Related ◽  
Reference Limits ◽  
Males And Females

Abstract Using a discrete analyzer and a dye-binding method, we measured magnesium in 800 patients' samples received for routine analysis. By excluding data from samples for which the calcium and (or) alkaline phosphatase values were outside defined reference limits, we established a reference interval for magnesium. Because the data showed a gaussian distribution, we could use parametric analysis to establish age-related intervals for both males and females.

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