Gastroenterology Board Prep

GERD, IBS, IBD, hepatitis, and colorectal cancer screening dominate ABFM GI questions. Daily practice grounded in AGA, ACG, and USPSTF recommendations.

Gastroenterology contributes roughly 6 to 8 percent of the ABFM Family Medicine boards. The content distribution favors common outpatient conditions: GERD, irritable bowel syndrome, hepatitis screening and management, peptic ulcer disease and H. pylori, and colorectal cancer screening. Inflammatory bowel disease and acute abdominal conditions appear less often but reliably. Liver disease — including cirrhosis complications, alcohol-associated liver disease, and metabolic dysfunction-associated steatotic liver disease (MASLD, formerly NAFLD) — is increasingly tested as the prevalence of fatty liver climbs in primary care.

Colorectal cancer screening is one of the highest-yield topics on the entire ABFM, not just within GI. The USPSTF lowered the screening start age to 45 in 2021 (Grade B), and most ABFM questions test this updated threshold. Average-risk screening options include colonoscopy every 10 years, FIT annually, FIT-DNA every 1 to 3 years, flexible sigmoidoscopy every 5 years (with FIT every year), and CT colonography every 5 years. Stop screening at age 75 for average-risk patients, with individualized decisions between 76 and 85. Higher-risk patients (family history, IBD, hereditary syndromes) need earlier and more frequent screening — know the specific guidelines.

GERD management has shifted toward shorter PPI courses and earlier endoscopy for alarm features. The American College of Gastroenterology recommends 8 weeks of PPI therapy for typical reflux symptoms; if symptoms persist or alarm features are present (dysphagia, weight loss, anemia, melena, age over 50 with new symptoms), endoscopy is warranted. H. pylori testing is no longer routine for uncomplicated GERD — reserve it for ulcer history, MALT lymphoma, or unexplained iron deficiency anemia.

Hepatitis B and C screening have expanded substantially. The USPSTF recommends one-time hepatitis C screening for all adults over 18, regardless of risk, and ongoing screening for high-risk patients. Hepatitis B screening is recommended for all adolescents and adults at risk, with universal hepatitis B vaccination of all adults under 60 (and over 60 with risk factors) per the 2022 ACIP update. Treatment of chronic hepatitis C with direct-acting antivirals (DAAs) has greater than 95 percent cure rates and is increasingly managed in primary care.

Irritable bowel syndrome is tested through Rome IV criteria and a positive symptom-based diagnosis approach. Limited workup (CBC, CRP, celiac serology, fecal calprotectin if IBS-D) rules out organic disease in most patients. Treatment is symptom-targeted: soluble fiber for IBS-C, low-FODMAP diet, antispasmodics, peppermint oil, and second-line agents like linaclotide or rifaximin for refractory cases. Distinguishing IBS from IBD using calprotectin is a high-yield testable concept.

High-yield gastroenterology topics

ABFM exam tips

Anchor on age 45 for colorectal cancer screening start. This is the single most-tested GI update on recent ABFM exams. If a patient is 45 to 49 and has not had screening, the answer is "start screening." If a question lists screening starting at 50, that is testing whether you know the 2021 USPSTF update.

Calculate FIB-4 for any abnormal LFTs in a metabolic syndrome patient. FIB-4 uses age, AST, ALT, and platelet count to estimate fibrosis risk. Under 1.3 means low risk; over 2.67 means high risk and warrants hepatology referral. The exam tests this risk stratification directly.

For GERD, recognize alarm features cold. Dysphagia, odynophagia, weight loss, GI bleeding, anemia, persistent vomiting, and age over 50 with new symptoms. Any of these triggers endoscopy referral, not another PPI trial.

For H. pylori, know when to test (and when not to). Test in PUD, MALT lymphoma, unexplained iron deficiency, and family history of gastric cancer. Do not test routinely for GERD, dyspepsia without alarm features in young patients (treat empirically), or asymptomatic individuals.

For hepatitis C, screen everyone over 18 once. This is a USPSTF Grade B recommendation that frequently appears on the boards. Confirm a positive antibody with HCV RNA. DAA treatment is now a primary care responsibility in many systems and is testable.

Use fecal calprotectin to distinguish IBS from IBD. Elevated calprotectin (over 150) suggests IBD or other organic disease and warrants colonoscopy. Normal calprotectin in an otherwise classic IBS presentation supports the diagnosis without colonoscopy.

Common pitfalls

Do not start colorectal cancer screening at 50. The USPSTF lowered the start age to 45 in 2021. Older study materials still reference 50, and this is a tested error. The shift was driven by rising early-onset colorectal cancer rates and modeling data showing benefit at 45.

Do not test for H. pylori in routine GERD. GERD is acid reflux, not an H. pylori-driven condition. Routine testing is low-yield and treatment with antibiotics is not benign. Reserve testing for ulcer disease, MALT lymphoma, and other specific indications.

Do not use clarithromycin-based triple therapy as first-line for H. pylori. US clarithromycin resistance now exceeds 15 percent in most regions, which makes triple therapy underperform. Bismuth quadruple therapy (PPI plus bismuth, tetracycline, metronidazole) for 14 days is preferred unless local resistance data say otherwise.

Do not over-rely on AST/ALT for liver disease severity. Patients with cirrhosis often have normal or only modestly elevated transaminases. Use platelet count, albumin, INR, bilirubin, and FIB-4 to assess hepatic synthetic function and fibrosis. A normal ALT does not rule out advanced liver disease.

Do not miss diverticulitis red flags. Most uncomplicated diverticulitis can be managed outpatient with bowel rest and (in select patients) antibiotics. Refer or admit for fever over 38.5, leukocytosis, peritonitis, abscess, perforation, or immunocompromise. Recent guidelines de-emphasize antibiotics in mild uncomplicated cases — this is testable.

Do not assume every diarrhea is infectious. Chronic diarrhea (over 4 weeks) with weight loss, blood, or nocturnal symptoms warrants workup for IBD, malabsorption, microscopic colitis, or malignancy. Microscopic colitis is a frequent miss in older women on NSAIDs or PPIs and requires biopsy to diagnose.

Do not forget hepatitis B vaccination in adults. ACIP now recommends universal hepatitis B vaccination for all adults under 60, and adults 60 and older with risk factors. This expanded recommendation from 2022 is tested as a preventive care item and is frequently missed.

Frequently asked questions

When should colorectal cancer screening start per the ABFM?

Age 45 for average-risk adults, per the 2021 USPSTF Grade B recommendation. Earlier for high-risk groups: age 40 or 10 years before the youngest affected first-degree relative for family history, or earlier per specific guidelines for IBD or hereditary syndromes. Stop at age 75 for average-risk patients; individualize 76 to 85.

How is H. pylori treated on current boards?

First-line in most US settings is bismuth quadruple therapy (PPI plus bismuth subsalicylate, tetracycline, and metronidazole) for 14 days. Clarithromycin-based triple therapy is no longer preferred due to resistance rates above 15 percent. Confirm eradication 4 weeks after treatment with stool antigen or urea breath test, off PPI for at least 2 weeks.

What is MASLD and how is it different from NAFLD?

MASLD (metabolic dysfunction-associated steatotic liver disease) is the new name for NAFLD as of 2023, reflecting the metabolic etiology. Diagnosis requires hepatic steatosis plus at least one cardiometabolic risk factor (overweight, diabetes, dyslipidemia, hypertension). The 2023 nomenclature change is showing up on recent ABFM exams.

How much GI content is on the ABFM?

Gastroenterology typically makes up 6 to 8 percent of the ABFM exam, or roughly 18 to 25 questions. Colorectal cancer screening, GERD, IBS, hepatitis, and H. pylori account for the majority. Liver disease (especially MASLD and alcohol-associated liver disease) is a growing topic area.

Should I screen all adults for hepatitis C?

Yes. The USPSTF recommends one-time HCV antibody screening for all adults 18 and older, regardless of risk factors, as a Grade B recommendation. Repeat screening is indicated for ongoing risk (injection drug use, hemodialysis, healthcare exposure). This is one of the most-tested preventive items on the ABFM.

What workup is appropriate for new IBS symptoms?

Apply Rome IV criteria first. If criteria are met, do limited workup: CBC, CRP, celiac serology (anti-tissue transglutaminase IgA), and fecal calprotectin (especially in IBS-D). Colonoscopy is reserved for alarm features (age over 45, weight loss, GI bleeding, family history of colorectal cancer, elevated calprotectin) or refractory symptoms.

When should I refer GI patients to specialists?

Endoscopy referral for GERD with alarm features, dyspepsia in patients over 60, suspected IBD, or workup for gastric cancer. Hepatology referral for FIB-4 over 2.67, decompensated cirrhosis, or hepatitis C treatment if not comfortable in primary care. Surgical or GI referral for complicated diverticulitis, refractory IBD, or any suspicion of malignancy.