What annual lab tests are recommended for a 45-year-old male with hypercholesterolemia, obesity, and hypertension who takes Metformin (Metformin), Zepbound (tirzepatide), Simvastatin (Simvastatin), Losartan (Losartan), follows an OMAD (One Meal A Day), ketogenic-leaning diet, takes daily electrolytes, creatine, and engages in resistance training?

Annual Laboratory Monitoring Recommendations

For this 45-year-old male with multiple cardiovascular risk factors on stable medication regimens, obtain a comprehensive metabolic panel, lipid profile, HbA1c, CBC, and electrolytes annually, with additional monitoring of creatine kinase and vitamin B12 given his specific medication and supplement profile.

Core Annual Laboratory Panel

Lipid Monitoring

• Obtain a lipid profile (total cholesterol, LDL-C, HDL-C, triglycerides) annually while on stable simvastatin therapy to monitor medication adherence and efficacy 1.
• At age 45 with established hypercholesterolemia and multiple ASCVD risk factors (obesity, hypertension), this patient requires ongoing lipid surveillance even when stable 1.
• The primary purpose of annual monitoring in stable patients is to assess medication adherence rather than just efficacy 2.

Diabetes Screening and Monitoring

• Obtain HbA1c annually given metformin use (2g/day) and multiple metabolic risk factors including obesity 3.
• While metformin suggests either prediabetes or type 2 diabetes, annual HbA1c monitoring is essential for patients with diabetes or at high risk 3.
• Fasting glucose should be included as part of the comprehensive metabolic panel 3.

Renal Function and Electrolytes

• Comprehensive metabolic panel including serum creatinine with eGFR, electrolytes (sodium, potassium, chloride, bicarbonate), and liver function tests (ALT, AST, alkaline phosphatase, total bilirubin) should be obtained annually 3.
• Potassium monitoring is particularly critical given losartan (ARB) use at maximum dose (100mg), which increases hyperkalemia risk 1.
• The combination of losartan with daily electrolyte supplementation requires careful potassium surveillance to avoid dangerous hyperkalemia 1.
• Metformin requires annual renal function monitoring to assess for contraindications and dose adjustments 3.

Hematologic Monitoring

• Complete blood count (CBC) annually to monitor for potential metformin-associated vitamin B12 deficiency and anemia 3.
• Long-term metformin use is associated with vitamin B12 malabsorption, making CBC surveillance important 3.

Urinalysis

• Annual urinalysis with urine albumin-to-creatinine ratio (UACR) to screen for diabetic nephropathy and monitor cardiovascular risk 3.
• This is particularly important given the combination of hypertension, likely diabetes (metformin use), and obesity 3.

Medication-Specific Monitoring Considerations

Statin Monitoring (Simvastatin 40mg)

• Creatine kinase (CK) should be checked if muscle symptoms develop, though routine monitoring is not required in asymptomatic patients 1.
• Given his resistance training regimen, be aware that exercise-induced CK elevations can occur and should not be confused with statin myopathy 1.
• Liver function tests (ALT, AST) should be obtained annually as part of the comprehensive metabolic panel to monitor for hepatotoxicity 3.

Metformin Monitoring (2g/day)

• Vitamin B12 level should be checked annually or biennially given the high dose and long-term use implications 3.
• Renal function (creatinine/eGFR) is essential annually to ensure metformin safety, as it is contraindicated in significant renal impairment 3.

Tirzepatide (Zepbound) Monitoring

• Lipid panel monitoring is important as tirzepatide significantly improves triglycerides and lipoprotein levels beyond weight loss effects 4, 5.
• HbA1c and fasting glucose help track metabolic improvements, as tirzepatide reduces diabetes risk and improves glycemic parameters 5, 6.
• While tirzepatide has a favorable safety profile similar to GLP-1 receptor agonists, monitoring metabolic parameters helps document cardiovascular risk factor improvement 5, 6.

Losartan Monitoring (100mg - maximum dose)

• Serum potassium and creatinine must be monitored annually due to hyperkalemia and acute kidney injury risk with ARBs 1.
• This is especially critical given his daily electrolyte supplementation, which may contain potassium 1.

Diet and Supplement-Specific Considerations

Ketogenic-Leaning OMAD Diet

• Lipid profile monitoring is essential as ketogenic diets can affect LDL-C and triglyceride levels, though effects vary individually 1.
• Comprehensive metabolic panel including electrolytes is important given the combination of ketogenic diet, OMAD pattern, and daily electrolyte supplementation 3.
• Fasting glucose and HbA1c help assess glycemic control, which typically improves with ketogenic approaches but requires monitoring 3.

Creatine Supplementation

• Serum creatinine should be interpreted cautiously as creatine supplementation can elevate creatinine levels without true renal impairment 3.
• Consider using cystatin C-based eGFR if there is concern about renal function accuracy in the setting of creatine supplementation 3.

Daily Electrolyte Supplementation

• Serum electrolytes (sodium, potassium, magnesium, chloride) require annual monitoring to ensure supplementation is appropriate and not causing imbalances 3.
• The combination of losartan, ketogenic diet, and electrolyte supplementation creates particular risk for potassium abnormalities 1.

Resistance Training Considerations

• Baseline CK level may be helpful to establish his normal range given regular resistance training, which physiologically elevates CK 1.
• If muscle symptoms develop while on simvastatin, compare CK to baseline rather than standard reference ranges 1.
• Testosterone level could be considered given age, obesity, and resistance training goals, though not strictly required annually 3.

Additional Cardiovascular Risk Assessment

Blood Pressure Monitoring

• Annual blood pressure measurement using proper technique is essential given diagnosed hypertension on maximum-dose losartan 3.
• Home blood pressure monitoring should be encouraged to assess control adequacy 1.

Thyroid Function

• TSH annually is reasonable given obesity, metabolic syndrome features, and age, as hypothyroidism can worsen lipid profiles and cardiovascular risk 3.

Common Pitfalls to Avoid

• Do not overlook potassium monitoring in patients on ARBs with electrolyte supplementation—this combination significantly increases hyperkalemia risk 1.
• Do not attribute elevated creatinine solely to renal disease without considering creatine supplementation effects; use cystatin C if needed 3.
• Do not assume lipid goals are met without annual verification, as medication adherence and dietary patterns can change 1, 2.
• Do not forget vitamin B12 monitoring in long-term, high-dose metformin users, as deficiency develops insidiously 3.
• Do not interpret CK elevations as statin myopathy without considering resistance training effects; obtain baseline CK for comparison 1.

Summary Laboratory Panel

Annual testing should include:

• Comprehensive metabolic panel (electrolytes, creatinine/eGFR, glucose, liver enzymes) 3
• Lipid profile (total cholesterol, LDL-C, HDL-C, triglycerides) 1
• HbA1c 3
• Complete blood count 3
• Urinalysis with UACR 3
• TSH 3
• Vitamin B12 (annually or every 2 years) 3

Consider obtaining:

• Baseline creatine kinase (for future reference if muscle symptoms develop) 1
• Cystatin C-based eGFR if creatinine appears elevated 3