Endocrine & Diabetes Board Prep

Diabetes management dominates this content area. Build fluency with the ADA Standards of Care, thyroid workup, and adrenal pearls in short daily sessions.

Endocrinology, and especially diabetes, is one of the most heavily tested content areas on the ABFM Family Medicine boards. Diabetes alone can account for 6 to 8 percent of the exam, with the broader endocrine category — thyroid disease, adrenal disorders, and lipid metabolism — adding another 4 to 5 percent. Together, endocrine content typically rivals cardiology for total question count. That makes sense: type 2 diabetes affects more than one in ten American adults, and family physicians manage the overwhelming majority of these patients without endocrinology referral.

The ADA Standards of Medical Care in Diabetes is updated annually and is the single most important reference for ABFM diabetes questions. The 2025 edition continues to emphasize an individualized A1c target (typically under 7 percent for most non-pregnant adults, with relaxation to 7.5 or 8 percent for older patients with comorbidities or limited life expectancy), early use of metformin as first-line therapy, and the addition of GLP-1 receptor agonists or SGLT2 inhibitors when there is established cardiovascular disease, heart failure, or chronic kidney disease — independent of A1c. This shift toward organ-protective therapy is a critical update that older board prep materials often miss.

Thyroid disease is the second-most tested endocrine topic. The exam favors hypothyroidism over hyperthyroidism by a factor of about two to one, reflecting prevalence in primary care. Subclinical hypothyroidism (elevated TSH, normal free T4) is a particular favorite, as is the workup of an incidentally discovered thyroid nodule. Know the TSH-first algorithm cold: a normal TSH essentially rules out primary thyroid disease, an elevated TSH with low free T4 is overt hypothyroidism, and an elevated TSH with normal free T4 is subclinical.

Adrenal disorders appear less frequently but reliably. The most common scenarios are adrenal incidentaloma workup (initial labs: dexamethasone suppression test, plasma metanephrines, aldosterone-renin ratio if hypertensive), recognition of primary adrenal insufficiency (hyperpigmentation, hyponatremia, hyperkalemia), and management of glucocorticoid-induced suppression. Cushing syndrome, pheochromocytoma, and primary hyperaldosteronism are tested mostly through their screening labs.

Finally, the boundary between endocrine and other content areas matters. Lipid management is split between cardiology and endocrine on the exam blueprint — the ABFM does not always tell you which category a question belongs to. Calcium and bone metabolism (osteoporosis, primary hyperparathyroidism, vitamin D deficiency) sits at the boundary between endocrine and women's health. Treat them as a single integrated body of knowledge.

High-yield endocrine & diabetes topics

• Diabetes pharmacotherapy by comorbidity (ADA 2025). Metformin is first-line. Add a GLP-1 receptor agonist (semaglutide, liraglutide) for established ASCVD or for weight loss benefit. Add an SGLT2 inhibitor (empagliflozin, dapagliflozin) for heart failure or CKD. These choices are independent of A1c.
• Diabetes screening and diagnosis. USPSTF recommends screening adults age 35 to 70 with overweight or obesity. Diagnose with A1c 6.5 or higher, fasting glucose 126 or higher, 2-hour OGTT 200 or higher, or random glucose over 200 with symptoms. Confirm on a separate day unless unequivocal hyperglycemia.
• Subclinical hypothyroidism management. Treat if TSH over 10, or TSH 7 to 10 in patients under 70 with symptoms or positive TPO antibodies. For TSH 4.5 to 7, observe and recheck in 6 to 12 weeks. Older patients tolerate higher TSH; do not over-treat asymptomatic mild elevations in patients over 70.
• Diabetic ketoacidosis vs hyperosmolar hyperglycemic state. DKA: glucose over 250, anion gap acidosis, ketones present, more common in type 1. HHS: glucose over 600, osmolality over 320, minimal ketosis, more common in type 2 and elderly. Both need IV fluids first, then insulin and electrolyte replacement (especially potassium).
• Thyroid nodule workup. Start with TSH and ultrasound. If TSH is suppressed, get a thyroid uptake scan (hot nodule = unlikely cancer, no FNA needed). If TSH is normal or elevated, biopsy based on ultrasound features per ATA criteria — generally nodules over 1 cm with suspicious features.
• Adrenal incidentaloma initial workup. Every adrenal mass needs screening for hormonal activity: 1 mg overnight dexamethasone suppression test (Cushing), plasma free metanephrines or 24-hour urine metanephrines (pheochromocytoma), and aldosterone-renin ratio if hypertensive (primary aldosteronism).
• Osteoporosis screening and treatment. DEXA at age 65 for women, 70 for men, or earlier with risk factors (FRAX 10-year hip fracture risk over 3 percent). Bisphosphonates (alendronate, risedronate) are first-line. T-score at or below -2.5 or fragility fracture at any T-score warrants treatment.
• Diabetic nephropathy screening and management. Annual urine albumin-to-creatinine ratio and eGFR in all diabetics. ACE inhibitor or ARB if albuminuria is present, regardless of blood pressure. SGLT2 inhibitor if eGFR is 20 or higher and albuminuria. Finerenone if albuminuria persists despite ACE/ARB.

ABFM exam tips

The ADA Standards update annually — use the most recent version. The 2025 ADA standards emphasize individualized A1c goals, organ-protective therapy choices (GLP-1s, SGLT2s), and continuous glucose monitoring access. Questions tested today reflect 2024 or 2025 standards, not 2020 standards.

Memorize the diagnostic thresholds for diabetes. A1c 6.5, fasting glucose 126, 2-hour OGTT 200, random 200 with symptoms. Prediabetes: A1c 5.7 to 6.4, fasting 100 to 125, 2-hour OGTT 140 to 199. The exam tests these numbers directly.

For thyroid questions, always start with TSH. When the question stem says "patient has fatigue and weight gain," your first move is TSH. If TSH is given, interpret it: high TSH means hypothyroid (recheck free T4), low TSH means hyperthyroid (check free T4 and free T3, consider uptake scan).

Know the diabetic complication screening schedule. Annual eye exam, annual urine albumin-to-creatinine ratio and eGFR, annual foot exam, lipid panel and BP every visit. The exam loves to test which screening is overdue when given a vignette listing what was done last year.

Recognize secondary causes of hypertension. Young patient with severe hypertension, low potassium, or paradoxical resistance to multiple drugs should trigger workup for primary aldosteronism (aldosterone-renin ratio), pheochromocytoma (metanephrines), or renal artery stenosis (imaging).

For osteoporosis, anchor on the FRAX threshold. A 10-year major osteoporotic fracture risk over 20 percent or hip fracture risk over 3 percent triggers pharmacologic treatment. T-score under -2.5 or any fragility fracture also qualifies. Bisphosphonates are first-line for nearly everyone.

Common pitfalls

Do not start basal insulin too early in type 2 diabetes. Modern ADA guidelines favor adding GLP-1 agonists or SGLT2 inhibitors before basal insulin in most patients without severe hyperglycemia. Insulin still has a role, but the old "metformin then insulin" pathway is outdated.

Do not over-treat subclinical hypothyroidism in elderly patients. A TSH of 6 in an 80-year-old is often appropriate physiology, not pathology. Treating to a "normal" TSH increases atrial fibrillation and osteoporosis risk in older adults. Treat only if symptomatic with clear evidence of benefit.

Do not forget to check potassium before starting an ACE inhibitor in diabetic nephropathy. Hyperkalemia is the most common reason these drugs get stopped. Check baseline potassium and creatinine, recheck in two weeks, and continue monitoring at least every six months.

Do not confuse type 1 and type 2 diabetes treatment paradigms. A young, lean patient with new diabetes and DKA needs insulin, not metformin. Look for clues: weight loss, ketones, autoimmune family history, age under 30. Adult-onset type 1 (latent autoimmune diabetes of adults, LADA) is a real entity and is occasionally tested.

Do not start metformin without checking eGFR. Metformin is contraindicated below eGFR 30 and should be dose-reduced between 30 and 45. The lactic acidosis risk is real but small; the bigger error is missing it on a routine kidney function check.

Do not forget that thyroid hormone needs to be taken on an empty stomach. Calcium, iron, PPIs, and food all impair absorption. A patient with persistently elevated TSH despite "adequate" levothyroxine is often actually nonadherent or taking it with breakfast.

Do not over-rely on TSH alone in central hypothyroidism. Pituitary disease causes low or normal TSH with low free T4. If a patient looks hypothyroid but TSH is normal, check free T4 anyway — central hypothyroidism gets missed when you stop at TSH.

Frequently asked questions

How much of the ABFM exam is endocrine and diabetes?

Endocrine content typically makes up 10 to 12 percent of the ABFM exam, with diabetes alone accounting for 6 to 8 percent. That places it among the top three content areas. Expect roughly 30 to 35 endocrine questions across a full exam, with the majority focused on diabetes management and thyroid disease.

Which diabetes guidelines does the ABFM test?

The ADA Standards of Medical Care in Diabetes is the primary reference. The exam reflects the most recent version available, so for a 2025 or 2026 sitting, prepare from the 2024 or 2025 ADA Standards. The KDIGO guidelines for diabetic kidney disease and the AACE algorithm also inform some questions, but ADA is the dominant source.

Should I memorize specific diabetes drug doses?

Generally no. The ABFM tests drug class selection more than dose titration. Know that metformin starts at 500 mg daily and titrates up, that semaglutide is weekly, that SGLT2 inhibitors are once daily, and that basal insulin starts at roughly 0.1 to 0.2 units per kilogram. Beyond that, focus on indications and contraindications.

How is thyroid disease tested on the boards?

Thyroid questions usually start with a vignette of fatigue, weight change, or an incidentally found nodule. The exam wants you to order TSH first, interpret it correctly, and choose appropriate next steps. Subclinical hypothyroidism, postpartum thyroiditis, and thyroid nodule workup are particular favorites.

Are GLP-1 agonists tested heavily on the ABFM?

Yes, increasingly so. Recent exams test when to add a GLP-1 receptor agonist (cardiovascular disease, weight management, A1c not at goal on metformin), how to counsel about GI side effects, and the difference between weekly injectables (semaglutide, dulaglutide) and oral semaglutide. Expect this category to grow on future exams.

What is the easiest way to remember diabetic complication screening?

Use the mnemonic "EARS": Eye exam annually, Albumin-to-creatinine ratio annually, Renal function (eGFR) annually, Sensory foot exam annually. Add lipids and blood pressure at every visit, and an A1c every 3 to 6 months depending on control. The exam loves to ask which screening is overdue.

Do I need to know the math for FRAX or ASCVD risk calculators?

No, the exam will give you the calculated number or describe a patient whose risk is clearly above or below threshold. You need to know the action thresholds (FRAX hip over 3 percent or major over 20 percent for treatment; ASCVD over 7.5 percent for moderate-intensity statin), not how to calculate the score by hand.