ElSayed NA, Aleppo G, Aroda VR, et al; on behalf of the American Diabetes Association; 2. Classification and diagnosis of diabetes: standards of care in diabetes—2023. Diabetes Care 2023;46(Suppl 1):S19–S40. https://doi.org/10.2337/dc23-S002

Sacks DB, Arnold M, Bakris GL, et al. Executive summary: guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus. Clin Chem 2023;69(8):777-84. https://doi.org/10.1093/clinchem/hvad079

Riddle MC, Cefalu WT, Evans PH, et al. Consensus report: definition and interpretation of remission in type 2 diabetes. Diabetes Care 2021;44(10):2438-44. https://doi.org/10.2337/dci21-0034

Diabetes Control and Complications Trial Research Group; Nathan DM, Genuth S, Lachin J et al. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 1993; 329(14):977-86. https://doi.org/10.1056/NEJM199309303291401

UK Prospective Diabetes Study (UKPDS) Group. Intensive blood- glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet 1998;352(9131):837-53. https://doi.org/10.1016/S0140-6736(98)07019-6

Stratton IM, Adler AI, Neil HAW, et al. Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): prospective observational study. BMJ 2000;321:405-12. https://doi.org/10.1136/bmj.321.7258.405

Rohlfing CL, Wiedmeyer H-M, Little RR, et al. Defining the relationship between plasma glucose and HbA1c: analysis of glucose profiles and HbA1c in the Diabetes Control and Complications Trial. Diabetes Care 2002;25(2):275–8. https://doi.org/10.2337/diacare.25.2.275

National Glycohemoglobin Standardization Program. Certified methods and laboratories. Updated 11/23. https://ngsp.org/certified.asp

Manley S, John WG, Marshall S. Introduction of IFCC reference method for calibration of HbA1c: implications for clinical care. Diabet Med 2004;21(7):673-6. https://doi.org/10.1111/j.1464-5491.2004.01311.x

https://www.diabetes.org.uk/professionals/position-statements-reports/diagnosis-ongoing-management-monitoring/new_diagnostic_criteria_for_diabetes

International Expert Committee. International Expert Committee report on the role of the A1C assay in the diagnosis of diabetes. Diabetes Care 2009;32(7):1327–34. https://doi.org/10.2337/dc09-9033

Dowd RP, Manning PW, Ahmed N, et al. Post introduction of HbA1c as a diagnostic test: consequences for requesting and reporting. Diabet Med 2015;32(Suppl 1):163(P440)

Gough S, Manley S, Stratton I (eds). HbA1c in diabetes: case studies using IFCC units Wiley Blackwell 2010. ISBN: 9781444334449

Manley S, Nightingale P, Stratton I, et al. Diagnosis of diabetes: HbA1c versus WHO criteria. Diabetes Primary Care 2010;12(2):87– 96

James J, Kong M‐F, Berrington R, Dhatariya K. Diabetes at the front door. A guideline from the Joint British Diabetes Society (JBDS) for Inpatient Care Group. JBDS 16. https://abcd.care/joint‐british‐diabetes‐societies‐jbds‐inpatient‐care‐group

Manley SE, Karwath A, Williams JA, et al. on behalf of the Diabetes Translational Research Group (DTRG), Queen Elizabeth Hospital Birmingham and Birmingham University. The use of HbA1c for new diagnosis of diabetes in those with hyperglycaemia on admission to or attendance at hospital urgently requires research. Br J Diabetes 2022;22(2):95-104. https://doi.org/10.15277/bjd.2022.386

Dowd RP, Round RA, Mason CL, et al. Review of HbA1c results >120 mmol/mol as patients may require urgent assessment if request for diagnosis of type 2 diabetes. Diabet Med 2014;31(Suppl 1):P466

Dowd RP, Round RA Mason CL, et al. Hyperglycaemia and diabetic ketoacidosis in patients presenting to hospital with HbA1c >13.1%/120 mmol/mol but no previous diagnosis of diabetes. Diabetes 2014;63(Suppl 1):A634 (2501-PO)

Sperling M, Bhowansingh R. Chorea hyperglycemia basal ganglia syndrome in a 63-year-old male. Case Reports in Medicine 2018, Article ID 9101207. https://doi.org/10.1155/2018/9101207

Ganapathy K, Palani R, Manley S, et al. Rare presentation of hyperglycaemia related ballistic movement. Dubai Diabetes Endocrinol J 2021;27:104. https://doi.org/10.1159/000518884

Bhattacharjee D, Vracar S, Round RA, et al. Utility of HbA1c assessment in people with diabetes awaiting liver transplantation. Diabet Med 2019;36(11):1444-52. https://doi.org/10.1111/dme.13870

Flamini M (2022). A holistic overview of hemoglobinopathies interactions with glycated hemoglobin. https://www.mlo-online.com/disease/diabetes/article/21276454/a-holistic-overview-of-hemoglobinopathies-interactions-with-glycated-hemoglobin, accessed March 12, 2023

Ghosh S, Manley SE, Nightingale PG, et al. Prevalence of admission plasma glucose in ‘diabetes’ or ‘at risk’ ranges in hospital emergencies with no prior diagnosis of diabetes by gender, age and ethnicity. Endocrinol Diab Metab 2020;3(3):e00140. https://doi.org/10.1002/edm2.140

Piso RJ, Walter P, Rudofsky G. False low HbA1c levels under treatment with ribavirin. J Clin Microbiol Lab Med 2018:JCMLM-101. https://doi.org/10.29011/JCMLM-101.100001

Carr J, Nightingale P, Round R, et al. Dapsone effects the accuracy of HbA1c measurements and can have implications for monitoring glycaemic control or diagnosis of diabetes. Br J Dermatol 2016; 175(Suppl S1):75(P111). https://doi.org/10.1111/bjd.14524

Shah AD, Fox RK, Rushakoff RJ. Falsely decreased HbA1c in a type 2 diabetic patient treated with dapsone. Endocr Pract 2014;20(11):229-32. https://doi.org/10.4158/EP14291.CR

Kadri F, Stuart K, Cramb R, et al. HbA1c interpretation and its caveats: a case of targeting apparently good glycaemic control causing severe hypoglycaemia. Abstract: 0550-P. International Diabetes Federation (IDF) meeting Vancouver, December 2015

Mostafa S, Webber J, Ganapathy K, et al. Complex presentations in people with diabetes: does HbA1c help or hinder. Diabet Med 2023;40(Suppl 1):P153. https://doi.org/10.1111/dme.15048

Morgan LJ, Syed AA, Carr-Smith J, et al. The relationship between HbA1c and fructosamine in patients with diabetes and sickle cell or haemoglobin D trait. Poster presented at the National Meeting of the Association for Clinical Biochemistry, Birmingham, 2008. Personal communication.

Use of glycated haemoglobin (HbA1c) in the diagnosis of diabetes mellitus: abbreviated report of a WHO consultation © World Health Organization 2011. PMID: 26158184

Manley SE, Susarla R, Round RA, et al. 1312-P: Admission plasma glucose and HbA1c in emergency hospital admissions by ethnicity. Diabetes 2019;68(Suppl 1):1312-P. https://doi.org/10.2337/db19-1312-P

Razi F, Khashayar P, Ghodssi-Ghassemabadi R, et al. Optimal glycated hemoglobin cutoff point for diagnosis of type 2 diabetes in Iranian adults. Can J Diabetes 2018;42(6):582-7. https://doi.org/10.1016/j.jcjd.2018.03.005

Williams JA, Karwath A, Round RA, et al. 133-LB: Relationship of HbA1c and glucose by ethnicity in UK Biobank. Diabetes 2022; 71(Suppl 1):133-LB. https://doi.org/10.2337/db22-133-LB

Costa FF, Rosário WR, Ribeiro Farias AC, et al. Metabolic syndrome and COVID-19: an update on the associated comorbidities and proposed therapies. Diabetes Metab Syndr 2020;14(5):809-14. https://doi.org/10.1016/j.dsx.2020.06.016

Reddy PK, Kuchay MS, Mehta Y, Mishra SK. Diabetic ketoacidosis precipitated by COVID-19: a report of two cases and review of literature. Diabetes Metab Syndr 2020;14(5):1459-62. https://doi.org/10.1016/j.dsx.2020.07.050

Diabetes in pregnancy: management of diabetes and its complications from preconception to the postnatal period (NICE Guideline [NG3]). Published: 25 February 2015

Nielsen LR, Ekbom P, Damm P, et al. HbA1c levels are significantly lower in early and late pregnancy. Diabetes Care 2004;27(5):1200-1. https://doi.org/10.2337/diacare.27.5.1200

Taylor R, Lee C, Kyne-Grzebalski D et al. Clinical outcomes of pregnancy in women with type 1 diabetes. Obstet Gynecol 2002;99(4):537-41. https://doi.org/10.1016/s0029-7844(01)01790-2

Carron Brown S, Kyne-Grzebalski D, Mwangi B, Taylor R. Effect of management policy upon 120 type 1 diabetic pregnancies: policy decisions in practice. Diabet Med 1999;16(7):573-8. https://doi.org/10.1046/j.1464-5491.1999.00124.x

Battelino T, Danne T, Bergenstal RM, et al. Clinical targets for continuous glucose monitoring data interpretation: recommend- ations from the international consensus on time in range. Diabetes Care 2019;42(8):1593 603. https://doi.org/10.2337/dci19-0028

Diabetes in pregnancy: management from preconception to the postnatal period (NICE Guideline [NG3]). Published: 25 February 2015 Last updated: 16 December 2020

Royal College of Obstetricians and Gynaecologists. Guidance for maternal medicine in the evolving coronavirus (COVID-19) pandemic. Information for healthcare professionals. Version 1: Published Monday 30 March 2020. London: RCOG, 2020

Keating N, Carpenter K, McCarthy K, et al. Clinical outcomes following a change in gestational diabetes mellitus diagnostic criteria due to the COVID-19 pandemic: a case-control study. Int J Environ Res Public Health 2022;19(3):1884. https://doi.org/10.3390/ijerph19031884

Curtis AM, Farmer AJ, Roberts NW, Armitage LC. Performance of guidelines for the screening and diagnosis of gestational diabetes mellitus during the COVID-19 pandemic: a scoping review of the guidelines and diagnostic studies evaluating the recommended testing strategies. Diabet Epidemiol Manag 2021;3:100023.

https://doi.org/10.1016/j.deman.2021.100023

Steven S, Hollingsworth KG, Al-Mrabeh A, et al. Very low-calorie diet and 6 months of weight stability in type 2 diabetes: pathophysiologic changes in responders and nonresponders. Diabetes Care 2016;39(5):808-15. https://doi.org/10.2337/dc15-1942

Leslie WS, Ford I, Sattar N, et al. The Diabetes Remission Clinical Trial (DiRECT): protocol for a cluster randomised trial. BMC Fam Pract 2016;17:20. https://doi.org/10.1186/s12875-016-0406-2

Nagi D, Hambling C, Taylor R. Remission of type 2 diabetes: a position statement from the Association of British Clinical Diabetologists (ABCD) and the Primary Care Diabetes Society (PCDS). Br J Diabetes 2019;19(1):73-6. https://doi.org/10.15277/bjd.2019.221

Taylor R. Type 2 diabetes and remission: practical management guided by pathophysiology. J Intern Med 2021;289(6):754–70. http://dx.doi.org/10.1111/joim.13214

Lim EL, Hollingsworth KG, Aribisala BS, et al. Reversal of type 2 diabetes: normalisation of beta cell function in association with decreased pancreas and liver triacylglycerol. Diabetologia 2011; 54(10):2506-14. https://doi.org/10.1007/s00125-011-2204-7

Lean MEJ, Leslie WS, Barnes AC, et al. Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open- label, cluster-randomised trial. Lancet 2018;391(10120):541-51. https://doi.org/10.1016/S0140-6736(17)33102-1

Karwath A, Williams JA, Round RA, et al. 973-P: By how much does red blood cell status affect the accuracy of HbA1c? Diabetes 2022;71(Suppl 1):973-P. https://doi.org/10.2337/db22-973-P

Tucker LA. Limited agreement between classifications of diabetes and prediabetes resulting from the OGTT, hemoglobin A1c, and fasting glucose tests in 7412 US adults. J Clin Med 2020;9(7):2207. https://doi.org/10.3390/jcm9072207

Chung WK, Erion K, Florez JC, et al. Precision medicine in diabetes: a consensus report from the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetologia 2020;63:1671-93. https://doi.org/10.1007/s00125-020-05181-w and Diabetes Care 2020;43:1617-35. https://doi.org/10.2337/dci20-0022

Manley SE, Stratton IM, Nightingale PG, et al. Increasing knowledge about HbA1c to improve patient outcomes using clinical audit as a research tool. Research symposium advancing precision diabetes medicine. Madrid, Spain 8-9 October 2019. Publication 2

Nolan JJ, Kahkoska AR, Semnani-Azad Z, et al. ADA/EASD Precision medicine in diabetes initiative: an international perspective and future vision for precision medicine in diabetes. Diabetes Care 2022;45(2):261-6. https://doi.org/10.2337/dc21-2216

Thornton-Swan TD, Armitage LC, Curtis AM, Farmer AJ. Assessment of glycaemic status in adult hospital patients for the detection of undiagnosed diabetes mellitus: a systematic review. Diabet Med 2022;39(4):e14777. https://doi.org/10.1111/dme.14777

Farmer AJ, Shine B, Armitage LC, et al. The potential for utilising in- hospital glucose measurements to detect individuals at high risk of previously undiagnosed diabetes: retrospective cohort study. Diabet Med 2022;39(10):e14918. https://doi.org/10.1111/dme.14918

Diabetes Prevention Programme 2018-19, Short Report. NHS Digital, Part of National Diabetes Audit. Publication Date: 13 Dec 2019.