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Nayeemuddin SN, Panigrahi A, Bhattacharjee R, Chowdhury S. Heterophilic Interference of Rheumatoid Factor in TSH Immunometric Assay: A Cross-Sectional Observational Study. Indian J Endocrinol Metab 2024; 28:29-34. [PMID: 38533277 PMCID: PMC10962763 DOI: 10.4103/ijem.ijem_99_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/10/2023] [Accepted: 04/26/2023] [Indexed: 03/28/2024] Open
Abstract
Introduction Considering the inherent vulnerability of immunoassays for heterophilic interference and the potential of Rheumatoid Factor (RF) to act as a heterophile-like antibody, we conducted this study to investigate if RF leads to any such heterophilic interference in seropositive rheumatoid arthritis (RA) patients. The study was done on the TSH assay as it is a noncompetitive, double antibody sandwich assay, which is known to be vulnerable to heterophilic interference. Methods In this cross-sectional observational study, eighty-four consecutive newly diagnosed RF-positive RA patients underwent TSH, Free T4, and anti-TPO estimation using the chemiluminescence technique (CLIA) on Siemens Immulite 1000 platform. The samples were screened for TSH interference using four methods: 1) analysis on a different platform, 2) assessment of linearity using doubling dilutions, 3) polyethylene glycol (PEG) precipitation, and 4) addition of a commercial blocker. Results Ten samples had a loss of linearity on serial dilution, indicating potential interference. After heterophile blocker treatment, five cases exhibited interference. One patient had diagnostic interpretation discordance on the second platform. No sample on PEG precipitation suggested the influence of antibodies. It is worth noting that even in cases where interference was suspected, the clinical interpretation was largely unaffected by the correction of TSH values based on mean dilution or measurement after heterophile blocker treatment. Conclusion RF can cause heterophilic interference in TSH immunoassays used commercially. However, in most cases, this interference does not affect clinical decision-making.
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Affiliation(s)
- Shaikh N. Nayeemuddin
- Department of Endocrinology, ESIC Medical College and Hospital, Hyderabad, Telangana, India
| | - Akash Panigrahi
- Department of General Medicine, Tata Main Hospital, Jamshedpur, Jharkhand, India
| | - Rana Bhattacharjee
- Department of Endocrinology, Medical College, Kolkata, West Bengal, India
| | - Subhankar Chowdhury
- Department of Endocrinology and Metabolism, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India
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Urbanschitz T, Burgener IA, Zeugswetter FK. Utility of a canine TSH assay for diagnosis and monitoring of feline hyperthyroidism. TIERARZTLICHE PRAXIS. AUSGABE K, KLEINTIERE/HEIMTIERE 2022; 50:93-100. [PMID: 35523163 DOI: 10.1055/a-1807-9546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
OBJECTIVE This retrospective study was initiated to evaluate the utility of TSH measurements using a common canine TSH assay to diagnose and monitor feline hyperthyroidism after radioiodine or thyreostatic drug treatment. MATERIAL AND METHODS The electronic database of the University of Veterinary Medicine Vienna was searched for combined TSH and T4 measurements. 217 pairs of TSH and T4 from 136 cats with possible hyperthyroidism were assigned to group A (untreated; n = 24) and B (treated; n = 193). Measurements in group B were then subcategorized according to T4 concentrations (reference range 15-50 nmol/L): group B1 = elevated T4 (n = 46), group B2 = normal T4 (n = 84) and group B3 = decreased T4 (n = 63). Group B2 was further divided into cats with low normal (group B2a; n = 35), medium normal (group B2b; n = 29) and high normal (group B2c; n = 20) T4 concentrations. RESULTS TSH was detectable in 4 (17 %) of the 24 untreated cats (group A) and did not return to normal despite seemingly successful therapy in two. Increased TSH concentrations were observed in 3.6 % of the treated cats in group B2 and 2.9 %, 6.9 %, and 0 % in subgroups B2a, B2b and B2c, respectively. Forty-four percent of the treated cats with a decreased T4 (group B3) had an increased TSH concentration. TSH correlated with treatment length (r = 0.358, p = 0.004) and was significantly higher in cats treated for more than 3 months (p = 0.008). CONCLUSION TSH was detectable in a significant number of untreated hyperthyroid cats and thus this parameter should not be used to definitively rule out feline hyperthyroidism. Furthermore, the very low prevalence of increased TSH concentrations in treated hyperthyroid cats with a normal T4 and cost benefit calculations do not support the routine measurement of TSH in these cats. The fact that TSH correlated with time since treatment start and 56 % of the cats with a decreased T4 had TSH concentrations within the reference limits, suggests delayed recovery of the pituitary thyrotrophs which might explain the low prevalence of subclinical hypothyroidism in the present study. CLINICAL RELEVANCE TSH measurement in cats with suspected or treated hyperthyroidism using a canine assay lacks diagnostic sensitivity and can only complement therapeutic decision-making.
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Affiliation(s)
| | - Iwan A Burgener
- Department for Small Animals and Horses, University of Veterinary Medicine, Division of small animal internal medicine
| | - Florian K Zeugswetter
- Department for Small Animals and Horses, University of Veterinary Medicine, Division of small animal internal medicine
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Ghazal K, Brabant S, Prie D, Piketty ML. Hormone Immunoassay Interference: A 2021 Update. Ann Lab Med 2022; 42:3-23. [PMID: 34374345 PMCID: PMC8368230 DOI: 10.3343/alm.2022.42.1.3] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/08/2021] [Accepted: 07/21/2021] [Indexed: 12/17/2022] Open
Abstract
Immunoassays are powerful qualitative and quantitative analytical techniques. Since the first description of an immunoassay method in 1959, advances have been made in assay designs and analytical characteristics, opening the door for their widespread implementation in clinical laboratories. Clinical endocrinology is closely linked to laboratory medicine because hormone quantification is important for the diagnosis, treatment, and prognosis of endocrine disorders. Several interferences in immunoassays have been identified through the years; although some are no longer encountered in daily practice, cross-reaction, heterophile antibodies, biotin, and anti-analyte antibodies still cause problems. Newer interferences are also emerging with the development of new therapies. The interfering substance may be exogenous (e.g., a drug or substance absorbed by the patient) or endogenous (e.g., antibodies produced by the patient), and the bias caused by interference can be positive or negative. The consequences of interference can be deleterious when clinicians consider erroneous results to establish a diagnosis, leading to unnecessary explorations or inappropriate treatments. Clinical laboratories and manufacturers continue to investigate methods for the detection, elimination, and prevention of interferences. However, no system is completely devoid of such incidents. In this review, we focus on the analytical interferences encountered in daily practice and possible solutions for their detection or elimination.
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Affiliation(s)
- Khaldoun Ghazal
- Assistance Publique Hopitaux de Paris, Department of Functional Explorations, Necker Enfants Malades Hospital, Paris-Centre University, Paris Cedex, France
| | - Severine Brabant
- Assistance Publique Hopitaux de Paris, Department of Functional Explorations, Necker Enfants Malades Hospital, Paris-Centre University, Paris Cedex, France
| | - Dominique Prie
- Assistance Publique Hopitaux de Paris, Department of Functional Explorations, Necker Enfants Malades Hospital, Paris-Centre University, Paris Cedex, France
| | - Marie-Liesse Piketty
- Assistance Publique Hopitaux de Paris, Department of Functional Explorations, Necker Enfants Malades Hospital, Paris-Centre University, Paris Cedex, France
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Haddad RA, Giacherio D, Barkan AL. Interpretation of common endocrine laboratory tests: technical pitfalls, their mechanisms and practical considerations. Clin Diabetes Endocrinol 2019; 5:12. [PMID: 31367466 PMCID: PMC6657094 DOI: 10.1186/s40842-019-0086-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/12/2019] [Indexed: 02/06/2023] Open
Abstract
Pitfalls in hormonal assays are commonly seen in clinical practice and may lead to erroneous clinical impressions and treatments. In this article, we address common laboratory pitfalls encountered during evaluation of patients with real or presumed endocrine disorders including high dose hook effect and falsely normal prolactin in cases of macroprolactinomas, macroprolactinemia and falsely elevated prolactin, macrothyrotropinemia and falsely elevated TSH, heterophile antibodies leading to false elevation of hormonal concentration, biotin interference with different hormonal assays, cross-reactivity of steroid hormones immunoassays, and others. We describe the mechanisms of such laboratory pitfalls, review clinical scenarios in which they might occur, and discuss the ways to resolve such conundrums. The aim of this article is to present a learning material for the endocrine trainees and practitioners.
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Affiliation(s)
- Raad A. Haddad
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical Center, 24 Frank Lloyd Wright, G-1500, Ann Arbor, MI 48106 USA
| | - Donald Giacherio
- Department of Pathology, University of Michigan Medical Center, Ann Arbor, MI USA
| | - Ariel L. Barkan
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical Center, 24 Frank Lloyd Wright, G-1500, Ann Arbor, MI 48106 USA
- Department of Neurosurgery, University of Michigan Medical Center, Ann Arbor, MI USA
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Favresse J, Burlacu MC, Maiter D, Gruson D. Interferences With Thyroid Function Immunoassays: Clinical Implications and Detection Algorithm. Endocr Rev 2018; 39:830-850. [PMID: 29982406 DOI: 10.1210/er.2018-00119] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/08/2018] [Indexed: 12/22/2022]
Abstract
Automated immunoassays used to evaluate thyroid function are vulnerable to different types of interference that can affect clinical decisions. This review provides a detailed overview of the six main types of interference known to affect measurements of thyroid stimulating hormone (TSH), free thyroxine (T4) and free triiodothyronine (T3): macro-TSH, biotin, antistreptavidin antibodies, anti-ruthenium antibodies, thyroid hormone autoantibodies, and heterophilic antibodies. Because the prevalence of some of these conditions has been reported to approach 1% and the frequency of testing for thyroid dysfunction is important, the scale of the problem might be tremendous. Potential interferences in thyroid function testing should always be suspected whenever clinical or biochemical discrepancies arise. Their identification usually relies on additional laboratory tests, including assay method comparison, dilution procedures, blocking reagents studies, and polyethylene glycol precipitation. Based on the pattern of thyroid function test alterations, to screen for the six aforementioned types of interference, we propose a detection algorithm, which should facilitate their identification in clinical practice. The review also evaluates the clinical impact of thyroid interference on immunoassays. On review of reported data from more than 150 patients, we found that ≥50% of documented thyroid interferences led to misdiagnosis and/or inappropriate management, including prescription of an unnecessary treatment (with adverse effects in some situations), inappropriate suppression or modification of an ongoing treatment, or use of unnecessary complementary tests such as an I123 thyroid scan. Strong interaction between the clinician and the laboratory is necessary to avoid such pitfalls.
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Affiliation(s)
- Julien Favresse
- Department of Laboratory Medicine, Cliniques Universitaires Saint-Luc and Université Catholique de Louvain, Brussels, Belgium
| | - Maria-Cristina Burlacu
- Service d'Endocrinologie et Nutrition, Cliniques Universitaires Saint-Luc and Université Catholique de Louvain, Brussels, Belgium
| | - Dominique Maiter
- Service d'Endocrinologie et Nutrition, Cliniques Universitaires Saint-Luc and Université Catholique de Louvain, Brussels, Belgium.,Pôle de recherche en Endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Cliniques Universitaires St-Luc and Université Catholique de Louvain, Brussels, Belgium
| | - Damien Gruson
- Department of Laboratory Medicine, Cliniques Universitaires Saint-Luc and Université Catholique de Louvain, Brussels, Belgium.,Pôle de recherche en Endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Cliniques Universitaires St-Luc and Université Catholique de Louvain, Brussels, Belgium
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Centanni M, Benvenga S, Sachmechi I. Diagnosis and management of treatment-refractory hypothyroidism: an expert consensus report. J Endocrinol Invest 2017; 40:1289-1301. [PMID: 28695483 PMCID: PMC5680379 DOI: 10.1007/s40618-017-0706-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/01/2017] [Indexed: 12/17/2022]
Abstract
There is a frequently encountered subset of hypothyroid patients who are refractory to standard thyroid hormone replacement treatment and require unexpectedly high doses of levothyroxine. In addition to clinical situations where hypothyroid patients are non-compliant, or where there is the possibility of excipient-induced disease exacerbation (gluten/celiac disease), therapeutic failure may be due to impaired absorption of the administered drug. The common approach to managing patients with unusual thyroxine needs is to escalate the dose of levothyroxine until targeted TSH levels are achieved. This approach can increase the risk for prolonged exposure to supratherapeutic doses of levothyroxine, which increase the chances of adverse outcomes. Repeated adjustments of levothyroxine can also escalate the costs of treatment, as frequent office visits and laboratory tests are required to determine and maintain the desired dose. Clinicians should take a systematic approach to managing patients whom they suspect of having treatment-refractory hypothyroidism. This may include searching for, and adjusting, occult medical conditions and/or other factors that may affect the absorption of levothyroxine, before up-titrating the dose of traditional levothyroxine therapy. Depending on the underlying pathology, another approach that may be considered is to try alternative formulations of levothyroxine that are less susceptible to intolerance issues related to excipients, or, in some cases, to malabsorption. The early discovery of these factors via a thoughtful patient work-up may avoid unnecessary thyroid medication adjustments and their consequences for both patients and clinicians.
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Affiliation(s)
- M. Centanni
- Section of Endocrinology, Department of Medico-surgical Services and Biotechnologies, Sapienza University of Rome, Latina, Italy
| | - S. Benvenga
- Section of Endocrinology, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
- Interdepartmental Program of Molecular and Clinical Endocrinology and Women’s Endocrine Health, A.O.U. Policlinico G Martino, Messina, Italy
| | - I. Sachmechi
- Division of Endocrinology, Queens Hospital Center, Icahn School of Medicine, Jamaica, NY USA
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Affiliation(s)
- Abdulaziz Ramadhan
- Division of Endocrinology and Metabolism, Department of Medicine, Jewish General Hospital, McGill University, Montréal, Que
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Ghosh S, Howlett M, Boag D, Malik I, Collier A. Interference in free thyroxine immunoassay. Eur J Intern Med 2008; 19:221-2. [PMID: 18395170 DOI: 10.1016/j.ejim.2007.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 05/10/2007] [Indexed: 11/17/2022]
Abstract
We report two patients who presented with non-specific symptoms of tiredness that prompted their clinician to order a thyroid function test. In both cases, free thyroxine (T4) was reported to be high, with a normal thyroid-stimulating hormone (TSH). Repeated blood tests from the same laboratory using the same assay method yielded similar results. Due to discrepancies between the clinical and laboratory findings, we decided to repeat the blood tests at another laboratory using a different assay method. This revealed normal free T4 and TSH levels, suggesting that heterophile antibodies were interfering with the free T4 assay, leading to clinical confusion.
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Affiliation(s)
- Sujoy Ghosh
- The Ayr Hospital, Dalmellington Road, Ayr KA6 6DX, United Kingdom.
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Duggal J, Singh S, Barsano CP, Arora R. Cardiovascular risk with subclinical hyperthyroidism and hypothyroidism: pathophysiology and management. ACTA ACUST UNITED AC 2007; 2:198-206. [PMID: 17786084 DOI: 10.1111/j.1559-4564.2007.06583.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Previous studies have suggested that subclinical thyroid dysfunction, as manifested by abnormalities in thyroid-stimulating hormone (TSH) levels, are associated with detrimental effects on the cardiovascular system. Subclinical hypothyroidism is characterized by abnormal lipid metabolism, cardiac dysfunction, diastolic hypertension conferring an elevated risk of atherosclerosis, and ischemic heart disease. Similarly, patients with subclinical hyperthyroidism have nearly 3 times the likelihood of atrial fibrillation over a 10-year follow-up interval, raising the question of whether patients with subclinical hyperthyroidism should be treated to prevent atrial fibrillation. A single measurement of low serum TSH in individuals aged 60 years or older has been reported to be associated with increased mortality from all causes and in particular from circulatory and cardiovascular disease in a 10-year follow-up study. Subclinical thyroid dysfunction is currently the subject of numerous studies and remains controversial, particularly as it relates to cardiovascular morbidity and mortality and clinical applications.
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Affiliation(s)
- Jasleen Duggal
- Department of Medicine, Chicago Medical School, Rosalind Franklin University of Medicine and Science; North Chicago, IL 60064, USA
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