What blood work is recommended before starting statin (HMG-CoA reductase inhibitor) therapy?

Blood Work Before Starting Statin Therapy

Obtain a lipid profile (total cholesterol, LDL, HDL, triglycerides) immediately before initiating statin therapy, and consider baseline liver transaminase measurement, but routine creatine kinase testing is not necessary. 1, 2, 3

Essential Pre-Treatment Laboratory Testing

Lipid Panel (Required)

• A complete lipid profile must be obtained immediately before starting statin therapy to establish baseline values and guide treatment intensity 1
• This includes: total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides 1
• The lipid panel serves as the foundation for determining appropriate statin intensity and monitoring response 1

Liver Function Tests (Recommended)

• Baseline hepatic transaminase levels (ALT, AST) should be measured before statin initiation to identify pre-existing liver conditions 2, 3
• The FDA and ACC recommend considering liver enzyme testing before starting therapy, particularly to detect modest elevations (<3 times upper limit of normal) that don't contraindicate statin use but require monitoring 2, 3
• Patients with baseline transaminase elevations <3x ULN can still safely start statins with appropriate follow-up 2

Creatine Kinase (NOT Routinely Required)

• Routine baseline creatine kinase measurement is NOT recommended before starting statins 1
• CK testing should only be performed if severe muscle symptoms develop during treatment, not as pre-treatment screening 1

Risk Factor Assessment Before Initiation

Identify Predisposing Factors for Side Effects

Before starting statins, assess for conditions that increase risk of statin-associated side effects 1:

• Age ≥65 years 3
• Uncontrolled hypothyroidism 3
• Renal impairment 3
• Chronic, stable liver disease (including non-alcoholic fatty liver disease) 1, 2
• Concomitant medications that interact with statins 3
• Asian ethnicity (higher risk for myopathy) 3
• Diabetes mellitus risk factors 1

Post-Initiation Monitoring

Follow-Up Lipid Testing

• Reassess lipid panel 4-12 weeks after starting statin therapy to monitor response and medication adherence 1
• Repeat lipid testing after any dose change 1
• Continue annual lipid monitoring thereafter 1

Liver Function Monitoring

• Routine periodic monitoring of liver enzymes after starting statins is NOT recommended if baseline levels were normal 1, 2
• Only check liver function tests if symptoms of hepatotoxicity develop: unusual fatigue, weakness, loss of appetite, abdominal pain, dark urine, or jaundice 2, 3
• If symptoms arise, measure full hepatic panel (AST, ALT, total bilirubin, alkaline phosphatase) 1

Muscle Enzyme Monitoring

• Routine creatine kinase monitoring during statin therapy is not useful 1
• Only measure CK if severe muscle symptoms, objective muscle weakness, or suspected rhabdomyolysis develops 1

Important Clinical Caveats

Special Populations Requiring Baseline Assessment

• Patients with chronic, stable liver disease: Obtain baseline measurements and establish a monitoring schedule before starting statins 1, 2
• Patients with severe renal impairment: Start at lower doses (5 mg rosuvastatin daily, maximum 10 mg daily) 3
• Asian patients: Initiate at 5 mg rosuvastatin daily due to higher myopathy risk 3

What NOT to Do

• Do not perform routine serial liver enzyme monitoring in asymptomatic patients—this practice was removed from FDA requirements 2, 4
• Do not check baseline CK unless the patient has pre-existing muscle symptoms 1
• Do not delay statin initiation for extensive laboratory workup beyond lipid panel and consideration of baseline transaminases 1, 2

Managing Abnormal Baseline Results

• ALT/AST <3x ULN: Safe to start statin with follow-up monitoring 2
• ALT/AST >3x ULN: Evaluate net benefit versus risk; may need to defer statin or use lower intensity 2
• Acute liver failure or decompensated cirrhosis: Absolute contraindication to statin therapy 3