Laboratory Interpretation and Clinical Correlation
Your patient's labs are essentially normal and do not explain his fatigue; the focus should remain on optimizing blood pressure control and sleep hygiene, with reassessment in one month as planned.
Key Laboratory Findings
Normal Results That Effectively Rule Out Common Causes
CBC is completely normal (WBC 6, Hgb 14.7, Hct 44.9, MCV 93, platelets 247), excluding anemia, polycythemia, and hematologic disorders as contributors to fatigue 1.
Renal function is excellent (Cr 0.8, eGFR 120), ruling out chronic kidney disease as a cause of fatigue or secondary hypertension 1.
Electrolytes are normal (Na 139, K 4.5, Cl 102, CO2 28), making primary aldosteronism—a common secondary cause of hypertension—extremely unlikely, as spontaneous or diuretic-induced hypokalemia is a hallmark feature 2.
Ferritin is normal at 283 ng/mL, excluding iron deficiency as a cause of fatigue 1.
Borderline/Mildly Abnormal Findings That Require Interpretation
Fasting Glucose 102 mg/dL (Borderline)
This represents impaired fasting glucose (100–125 mg/dL range), which warrants lifestyle modification but does not explain fatigue 1.
Recommend HbA1c testing to assess for prediabetes or early diabetes, as metabolic syndrome frequently coexists with hypertension and can contribute to cardiovascular risk 1, 3.
Counsel on weight loss, dietary modification (reduced refined carbohydrates), and increased physical activity 1.
AST 68 U/L (Mildly Elevated) with Normal ALT 35 U/L
The AST:ALT ratio is approximately 1.9:1, which suggests alcoholic liver disease as the most likely etiology when the ratio exceeds 2:1, though non-alcoholic fatty liver disease (NAFLD) can also present this way 4, 5.
Directly inquire about alcohol consumption using validated screening tools (AUDIT-C), as patients often underreport intake 4, 5.
The isolated AST elevation with normal ALT is not consistent with viral hepatitis, autoimmune hepatitis, or hemochromatosis, which typically elevate ALT more than AST 4, 5.
NAFLD remains possible given borderline glucose and family history of hypertension (suggesting metabolic syndrome clustering), but the AST:ALT pattern is atypical 4, 5.
No further hepatic workup is indicated at this time if alcohol use is minimal and the patient has no risk factors for chronic liver disease; repeat liver enzymes in 3–6 months after lifestyle modification 4, 5.
Total Bilirubin 1.4 mg/dL (Mildly Elevated) with Direct Bilirubin 0
Unconjugated hyperbilirubinemia (elevated total with normal direct) most commonly represents Gilbert syndrome, a benign genetic condition affecting 3–7% of the population 4.
Gilbert syndrome causes no symptoms, no liver dysfunction, and requires no treatment; it is often unmasked by fasting, illness, or stress 4.
The combination of normal ALT, normal alkaline phosphatase, and isolated unconjugated hyperbilirubinemia excludes hepatocellular disease and cholestasis 4.
No further evaluation is needed for this finding 4.
Albumin 5.5 g/dL (High-Normal)
This likely represents hemoconcentration or laboratory variation and has no clinical significance in an otherwise healthy patient 1.
Albumin levels are typically low in chronic disease states; an elevated value does not suggest pathology 1.
Clinical Correlation with Presenting Symptoms
Fatigue
None of the laboratory abnormalities explain the patient's fatigue 1.
The most likely contributors remain:
Hypertension
Routine laboratory screening for secondary hypertension is complete and negative 1, 2.
Normal potassium excludes primary aldosteronism (8–20% of resistant hypertension) 2.
Normal creatinine and urinalysis (assumed normal based on your workup) exclude renovascular disease and renal parenchymal disease 1, 2.
No further workup for secondary hypertension is indicated unless blood pressure remains uncontrolled after 3–6 months of optimal medical therapy (≥3 medications including a diuretic) 1, 2.
Confirm the diagnosis of hypertension with home blood pressure monitoring or 24-hour ambulatory monitoring, as white-coat hypertension is common and can lead to overtreatment 1, 6.
Recommended Next Steps
Immediate Actions
Obtain HbA1c to screen for prediabetes/diabetes given fasting glucose 102 mg/dL 1, 3.
Assess alcohol consumption using a validated tool (AUDIT-C) to explain the AST:ALT pattern 4, 5.
Confirm hypertension diagnosis with home blood pressure monitoring (twice daily for 7 days) or 24-hour ambulatory monitoring before initiating pharmacotherapy 1, 6.
Obtain a 12-lead ECG as part of routine hypertension evaluation to screen for left ventricular hypertrophy, which is an independent predictor of cardiovascular events 1, 7.
Follow-Up at One Month
Reassess blood pressure after 5-day monitoring and sleep hygiene intervention 1.
Repeat liver enzymes (AST, ALT) in 3–6 months if alcohol use is minimal; no imaging or further workup is needed now 4, 5.
Evaluate response to sleep hygiene counseling; if insomnia persists despite adherence, consider cognitive-behavioral therapy for insomnia (CBT-I) as first-line treatment before pharmacotherapy 1.
Initiate antihypertensive therapy if home blood pressure remains ≥140/90 mmHg, starting with a thiazide-like diuretic (chlorthalidone or indapamide), ACE inhibitor/ARB, or calcium channel blocker based on patient factors 1.
Lifestyle Modifications (Reinforce at Follow-Up)
Dietary sodium restriction to <2400 mg/day (ideally <1500 mg/day) 1, 2.
Regular aerobic exercise (150 minutes/week of moderate-intensity activity) 1, 3.
Common Pitfalls to Avoid
Do not over-investigate the mildly elevated AST with extensive hepatic imaging or serologies in the absence of risk factors for chronic liver disease; the most common causes are alcohol and NAFLD, both managed with lifestyle modification 4, 5.
Do not dismiss the borderline glucose; this patient is at high risk for progression to diabetes and requires HbA1c testing and aggressive lifestyle intervention 1, 3.
Do not initiate antihypertensive therapy based on office readings alone without confirming sustained elevation with home or ambulatory monitoring, as approximately 30% of patients have white-coat hypertension 1, 6.
Do not pursue extensive workup for secondary hypertension in a 33-year-old with a family history of hypertension and normal screening labs; essential hypertension is far more likely 1, 2, 8.