Laboratory Testing for General Patient Evaluation
For a general patient without specific presenting complaints, draw a comprehensive metabolic panel, complete blood count with differential, thyroid-stimulating hormone (TSH), lipid panel, hemoglobin A1C, and urinalysis as the foundational laboratory evaluation. 1, 2, 3
Core Laboratory Panel (Tier 1 Testing)
Essential Tests for All Patients
Complete Blood Count (CBC) with differential to identify anemia, infection, leukemia, or other hematologic disorders that commonly present with nonspecific symptoms 1, 2, 3
Complete Metabolic Panel (Chem-20) including:
Thyroid-Stimulating Hormone (TSH) to screen for hypothyroidism or hyperthyroidism, both reversible causes of multiple symptoms 1, 2, 3
Lipid Panel (total cholesterol, LDL, HDL, triglycerides) for cardiovascular risk assessment 1, 3
Hemoglobin A1C for diabetes screening or monitoring 3
Urinalysis to screen for renal disease, diabetes, infection, or rhabdomyolysis 1, 2
Additional Baseline Tests to Consider
Vitamin B12 level as deficiency causes weakness, neuropathy, and cognitive impairment 2, 3
Inflammatory markers (ESR and CRP) to identify inflammatory or autoimmune conditions 2, 3
Liver function tests if not included in metabolic panel 1
Important Caveats and Clinical Context
Do NOT routinely order ALAT (ALT), calcium, or TSH in patients presenting with nonspecific complaints in the emergency department setting, as abnormal findings are relatively low and do not justify routine use. 4 However, these tests remain appropriate for outpatient screening and when specific clinical suspicion exists 1, 2, 3.
Tests to Avoid Without Specific Indication
Creatine kinase (CK) should only be ordered when muscle disease, myositis, or rhabdomyolysis is specifically suspected based on symptoms of true weakness (not fatigue), muscle pain, or dark urine 2
Troponin is only indicated when myocardial involvement is suspected, particularly if CK is elevated 2
Homocysteine adds value primarily when B12 deficiency is suspected or for vascular risk assessment 2, 3
Critical Interpretation Points
Distinguish screening from diagnostic testing: The above panel serves as screening in asymptomatic or minimally symptomatic patients; additional targeted testing should be guided by specific clinical findings 1, 2
Medication history is essential: Statins, corticosteroids, and other medications commonly cause laboratory abnormalities and symptoms, potentially avoiding extensive workup 2
Normal results do not exclude disease: Some conditions (inflammatory myopathies, early metabolic disorders) can present with normal or minimally abnormal laboratory values 2
All test results must be reviewed, understood, and followed up: Inadequate test result reporting and follow-up represents a major patient safety risk 5
When to Pursue Additional (Tier 2-4) Testing
Additional laboratory tests should be ordered using a deliberate, personalized, and judicious approach based on the patient's clinical characteristics and risk profile, not a broad-based "shotgun" approach. 1
Tier 2 Testing (Selective Use Based on Clinical Profile)
Consider when diagnostic uncertainty remains after initial evaluation:
- Autoantibody panels if autoimmune disease suspected 2
- Coagulation studies (PT/INR, aPTT) if bleeding disorder suspected 1
- Specific hormone testing beyond TSH if endocrine disorder suspected 1
Tier 3-4 Testing (Highly Selective, Often Requiring Specialist Input)
Reserve for atypical presentations or when diagnostic uncertainty persists: