Reference values for IGF-I serum concentration in an adult population: use of the VARIETE cohort for two new immunoassays

Sabbah, Nadia; Wolf, Peter; Piedvache, Céline; Trabado, Séverine; Verdelet, Tristan; Cornu, Catherine; Souberbielle, Jean‐Claude; Chanson, Philippe

doi:10.1530/ec-21-0175

Cited by 15 publications

(8 citation statements)

References 35 publications

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“…Inter-laboratory and inter-assay discrepancies with IGF-I assays are well known [ 6 , 13 , 14 ]; normal reference ranges are specific to each immunoassay, with the greatest differences seen at the highest values [ 6 ] (MQ). Well-validated IGF-I should be calibrated to the current international standard (02/254) [ 15 ].…”

Section: Diagnostic Assessmentmentioning

confidence: 99%

Consensus on criteria for acromegaly diagnosis and remission

Giustina,

Biermasz,

Casanueva

et al. 2023

Pituitary

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Purpose The 14th Acromegaly Consensus Conference was convened to consider biochemical criteria for acromegaly diagnosis and evaluation of therapeutic efficacy. Methods Fifty-six acromegaly experts from 16 countries reviewed and discussed current evidence focused on biochemical assays; criteria for diagnosis and the role of imaging, pathology, and clinical assessments; consequences of diagnostic delay; criteria for remission and recommendations for follow up; and the value of assessment and monitoring in defining disease progression, selecting appropriate treatments, and maximizing patient outcomes. Results In a patient with typical acromegaly features, insulin-like growth factor (IGF)-I > 1.3 times the upper limit of normal for age confirms the diagnosis. Random growth hormone (GH) measured after overnight fasting may be useful for informing prognosis, but is not required for diagnosis. For patients with equivocal results, IGF-I measurements using the same validated assay can be repeated, and oral glucose tolerance testing might also be useful. Although biochemical remission is the primary assessment of treatment outcome, biochemical findings should be interpreted within the clinical context of acromegaly. Follow up assessments should consider biochemical evaluation of treatment effectiveness, imaging studies evaluating residual/recurrent adenoma mass, and clinical signs and symptoms of acromegaly, its complications, and comorbidities. Referral to a multidisciplinary pituitary center should be considered for patients with equivocal biochemical, pathology, or imaging findings at diagnosis, and for patients insufficiently responsive to standard treatment approaches. Conclusion Consensus recommendations highlight new understandings of disordered GH and IGF-I in patients with acromegaly and the importance of expert management for this rare disease.

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Section: Diagnostic Assessmentmentioning

confidence: 99%

Consensus on criteria for acromegaly diagnosis and remission

Giustina,

Biermasz,

Casanueva

et al. 2023

Pituitary

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“…The group of Chanson and colleagues 8,9 has produced reference intervals for eight commercially available IGF-1 assay kits in one and the same cohort of healthy control samples. They demonstrated a large variability in the reference ranges of the eight studied IGF-1 assays, despite the fact that all IGF-1 assays were obtained in the same large healthy population and were calibrated against the same recommended standard.…”

Section: Follow-upmentioning

confidence: 99%

IGF‐1 as screening tool for acromegaly and adult‐onset growth hormone deficiency in the Netherlands

Postma,

van Beek,

van der Klauw

et al. 2023

Clinical Endocrinology

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ObjectiveInsulin‐like growth factor 1 (IGF‐1) measurements play a central role in the diagnosis and follow‐up of acromegaly and growth hormone deficiency. However, improving health care outcomes for these patients involves an intricate process of laboratory diagnostics and skilled health care professionals. The integrated effects of IGF‐1 reports on diagnosis and treatment decisions are yet unknown.Design, Patients and MeasurementsExtended quality assessment, distributing the description of five (real) patient cases with accompanying blood samples. Patients suspected or during follow up for acromegaly or adult onset of growth hormone deficiency were included. Laboratory specialists and endocrinologists in the same centre were asked to interpret their centre‐specific IGF‐1 results by using a laboratory and medical questionnaire. This way, insight could be obtained into the combined effects of different assays, assay harmonisation, reference value sets, and individual physician interpretation in relation to guidelines, thus reviewing the entire diagnostic and management process.ResultsLimited variation (CV 13.8 ± 2.8) was found in IGF‐1 concentrations despite different use of the harmonization sample and factor among laboratories. This interlaboratory variation increased upon conversion to SD scores (CV 15.7 ± 40.7) as a consequence of the use of different reference value sets. Furthermore, there was a lack of adherence to international guidelines among endocrinologists.ConclusionsHighly variable diagnostic and treatment outcomes in acromegaly and AGHD in the Netherlands can be attributed to increased variability of IGF‐1 upon conversion to SD scores and low adherence to clinical guidelines.

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“…These variations in assay agreement were independent of the use of mass units or SD scores. Given this variability, if possible, patients with GH disorders should be monitored using the same IGF-I assay at each assessment point (18).…”

Section: Considerations When Using Igf-i As a Biomarkermentioning

confidence: 99%

“…It has been suggested that conversion of IGF-I levels into sds could be used to solve the problem of reference interval variation across assays. However, large variability in the reference ranges of commercially available IGF-I assays, particularly in the upper limits of the reference range, has been found, with only moderate average concordance found across eight immunoassays ( 18 ). These variations in assay agreement were independent of the use of mass units or SDS.…”

Section: Role Of Precision Medicine In Accurate Biochemical Diagnosis...mentioning

confidence: 99%

“…These variations in assay agreement were independent of the use of mass units or SDS. Given this variability, if possible, patients with GH disorders should be monitored using the same IGF-I assay at each assessment point ( 18 ).

Figure 1 Reference intervals for (A) males and (B) females according to the age intervals of six insulin-like growth factor I (IGF-I) immunoassays.…”

Section: Role Of Precision Medicine In Accurate Biochemical Diagnosis...mentioning

confidence: 99%

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Applying precision medicine to the diagnosis and management of endocrine disorders

Bidlingmaier

Gleeson

Latrônico

et al. 2022

Endocrine Connections

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Precision medicine incorporates knowledge of a patient’s genetic makeup, environment and lifestyle for accurate diagnosis, and to develop individualised treatment and prevention strategies. Precision medicine has improved management in a number of disease areas, most notably in oncology, and it has the potential to positively impact others, including endocrine disorders. The accuracy of diagnosis in patients with growth disorders can be improved by using biomarkers. Insulin-like growth factor I (IGF-I) is the most widely accepted biomarker of growth hormone secretion, but its predictive value for recombinant human growth hormone treatment response is modest and various factors can affect the accuracy of IGF-I measurements. These factors need to be taken into account when considering IGF-I as a component of precision medicine in the management of growth hormone deficiency. The use of genetic analyses can assist with diagnosis by confirming the aetiology, and facilitate treatment decisions, guide counselling and allow prompt intervention in children with pubertal disorders, such as central precocious puberty and testotoxicosis. Precision medicine has also proven useful during the transition of young people with endocrine disorders from paediatric to adult services, when patients are at heightened risk of dropping out from medical care. An understanding of the likelihood of ongoing GH deficiency, using tools such as magnetic resonance imaging, detailed patient history and IGF-I levels, can assist in determining the need for continued recombinant human growth hormone treatment during the process of transitional care.

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Reference values for IGF-I serum concentration in an adult population: use of the VARIETE cohort for two new immunoassays

Cited by 15 publications

References 35 publications

Consensus on criteria for acromegaly diagnosis and remission

Consensus on criteria for acromegaly diagnosis and remission

IGF‐1 as screening tool for acromegaly and adult‐onset growth hormone deficiency in the Netherlands

Applying precision medicine to the diagnosis and management of endocrine disorders

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