What laboratory tests should I order for a patient?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: July 29, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

Laboratory Tests for Patient Evaluation

For a comprehensive patient evaluation, laboratory testing should include complete blood count, urinalysis, serum electrolytes, blood urea nitrogen, serum creatinine, glucose, lipid profile, liver function tests, iron studies, and thyroid-stimulating hormone. 1

Core Laboratory Tests for Initial Patient Assessment

Basic Testing (First-Line)

  • Complete blood count (CBC) with differential
  • Comprehensive metabolic panel including:
    • Serum electrolytes (sodium, potassium, calcium, magnesium)
    • Blood urea nitrogen (BUN)
    • Serum creatinine with estimated glomerular filtration rate (eGFR)
    • Glucose
    • Liver function tests (AST, ALT, alkaline phosphatase, bilirubin)
  • Lipid profile
  • Thyroid-stimulating hormone (TSH)
  • Urinalysis
  • Electrocardiogram (ECG)

The American College of Cardiology/American Heart Association guidelines strongly recommend this comprehensive panel of tests for initial patient evaluation to assess organ function, identify comorbidities, and establish baseline values 1.

Condition-Specific Additional Testing

Cardiovascular Assessment

  • Additional cardiac biomarkers if cardiac disease suspected:
    • Troponin
    • BNP/NT-proBNP (for heart failure)
  • Orthostatic blood pressure measurements to assess volume status 2

Hematologic Evaluation

  • Iron studies (serum iron, ferritin, transferrin saturation) 1
  • If eosinophilia present: serum tryptase, vitamin B12 levels 1

Autoimmune Disease Workup

For patients with suspected autoimmune conditions:

  • Erythrocyte sedimentation rate (ESR)
  • C-reactive protein (CRP)
  • Autoantibody panel as indicated:
    • ANA, anti-dsDNA, anti-Ro, anti-La, anti-RNP, anti-Sm, anti-phospholipid antibodies
    • Complement levels (C3, C4) 1

Endocrine Assessment

  • HbA1c for diabetes screening/monitoring
  • Additional thyroid function tests (T3, T4) if TSH abnormal

Special Considerations

Secondary Hypertension Workup

For patients with suspected secondary hypertension, consider:

  • Aldosterone-to-renin ratio
  • 24-hour urinary metanephrines (for pheochromocytoma)
  • Sleep study (for obstructive sleep apnea) 1

Kidney Disease Evaluation

For patients with abnormal urinalysis or elevated creatinine:

  • Urine protein/creatinine ratio
  • Urine microscopy
  • Renal ultrasound 1

Neurological/Cognitive Assessment

For patients with cognitive concerns:

  • Vitamin B12 levels
  • Folate levels
  • Syphilis serology
  • HIV testing (if risk factors present) 1

Monitoring Recommendations

Laboratory tests should be repeated based on:

  1. Clinical condition changes
  2. Medication adjustments (especially diuretics, RAS blockers)
  3. Disease-specific monitoring protocols

For patients with stable chronic conditions, laboratory monitoring every 6-12 months is generally appropriate 1.

Important Caveats

  • Laboratory results must always be interpreted in clinical context
  • Abnormal results should prompt appropriate follow-up testing
  • Consider preanalytical factors that may affect results (timing, fasting status, medications)
  • Cost-effectiveness should be considered when ordering extensive panels

The comprehensive approach outlined above ensures thorough evaluation of organ systems and establishes baseline values for future comparison, supporting early detection of disease and optimal management of existing conditions.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Hemoconcentration Diagnosis and Treatment

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.