Comprehensive Blood Work Recommendations for Diagnostic Evaluation
For a comprehensive diagnostic evaluation, initial laboratory tests should include complete blood count, urinalysis, serum electrolytes (including calcium and magnesium), blood urea nitrogen, serum creatinine, fasting blood glucose (glycohemoglobin), lipid profile, liver function tests, and thyroid-stimulating hormone. 1
Core Laboratory Tests
Essential Blood Tests
Complete Blood Count (CBC) with differential
- Evaluates red blood cells, white blood cells, and platelets
- Helps detect anemia, infections, and blood disorders
- Includes hemoglobin, hematocrit, white blood cell count with differential, and platelet count
Comprehensive Metabolic Panel (CMP)
- Electrolytes (sodium, potassium, chloride, bicarbonate)
- Kidney function (BUN, creatinine)
- Liver function tests (ALT, AST, alkaline phosphatase, bilirubin)
- Glucose
- Calcium, magnesium, phosphorus
Lipid Profile
- Total cholesterol
- LDL cholesterol
- HDL cholesterol
- Triglycerides
Thyroid Function
- Thyroid-stimulating hormone (TSH)
- Consider free T4 if TSH is abnormal
Urinalysis
- Screens for kidney disease, urinary tract infections, and diabetes
- Includes assessment for protein, glucose, blood, and signs of infection
Additional Important Tests
Hemoglobin A1C
- Measures average blood glucose over past 2-3 months
- Important for diabetes screening and monitoring
Inflammatory Markers
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP)
Specialized Tests Based on Clinical Context
Cardiovascular Assessment
- Cardiac enzymes (troponin, CK-MB) if cardiac symptoms present
- BNP/NT-proBNP if heart failure suspected
Hematologic Evaluation
- Coagulation studies (PT/INR, PTT) if bleeding disorder suspected
- Iron studies (ferritin, iron, TIBC) if anemia present
Infectious Disease Screening
- Blood cultures if infection suspected
- HIV, hepatitis B and C serologies if risk factors present
Autoimmune Evaluation
- Antinuclear antibodies (ANA)
- Rheumatoid factor (RF)
- Consider specific autoantibodies based on symptoms
Age and Gender-Specific Considerations
For Adults Over 65
- Vitamin B12 and folate levels
- Vitamin D level
- Consider bone health assessment (calcium, vitamin D, phosphorus)
- Cognitive performance assessment if indicated
For Women
- Pregnancy test if relevant
- Consider hormonal evaluation if indicated
Common Pitfalls to Avoid
Relying solely on laboratory values - Laboratory tests should always be interpreted in the context of clinical presentation 2
Ordering unnecessary tests - Targeted testing based on clinical presentation is more cost-effective than indiscriminate panels 3
Delaying critical interventions for test results - In emergent situations, do not delay treatment to wait for laboratory results 1
Missing follow-up testing - Abnormal results often require confirmatory or follow-up testing
Overlooking pre-test requirements - Some tests (like lipid profiles) may require fasting for accurate results
Follow-Up Testing Schedule
- Initial abnormalities: Repeat within 1-4 weeks depending on severity
- Medication monitoring: Follow specific guidelines for medications with known effects on laboratory values
- Chronic conditions: Regular monitoring as indicated by condition (typically every 3-6 months)
- Routine screening: Annual testing for stable patients
By following this comprehensive approach to laboratory testing, you can establish baseline values, identify abnormalities, monitor chronic conditions, and guide treatment decisions effectively.