Initial Test Orders for Patients with Unknown Symptoms
When evaluating a patient with undifferentiated symptoms, order a comprehensive metabolic panel, complete blood count with differential, thyroid function tests (TSH), lipid profile, urinalysis, fasting glucose/HbA1c, and inflammatory markers (CRP, procalcitonin) as first-tier laboratory testing. 1, 2
Core Laboratory Panel
The initial workup should include:
- Complete blood count with differential to detect cytopenias, thrombocytopenia, or eosinophilia that may indicate underlying systemic disease 1, 2
- Comprehensive metabolic panel including electrolytes (calcium, magnesium), renal function (creatinine), and hepatic function to assess organ dysfunction 1, 2
- Glucose metabolism assessment with fasting glucose and HbA1c to screen for diabetes and metabolic disorders 1
- Thyroid function tests (TSH) as thyroid dysfunction commonly presents with nonspecific symptoms 1
- Lipid profile to evaluate for dyslipidemia and metabolic abnormalities 1
- Urinalysis and fecal occult blood testing as part of basic screening 2
Inflammatory and Infection Markers
For patients with signs suggesting systemic infection or inflammation:
- C-reactive protein and procalcitonin should be measured when sepsis or severe infection is suspected 2
- Blood gas analysis if systemic infection or metabolic derangement is present 2
Age and Sex-Specific Testing
In male patients over 40 years, add prostate-specific antigen (PSA) to screen for occult prostate malignancy 2
In males with unexplained symptoms, consider alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (β-HCG) to exclude germ-cell tumors, particularly in younger patients 2
Physical Examination Priorities
The physical examination must be comprehensive and include:
- Head and neck examination including thyroid palpation 2
- Breast examination in all patients 2
- Digital rectal examination to assess for occult bleeding or masses 2
- Pelvic examination in females 2
- Lymph node assessment throughout all nodal basins 2
Common Pitfalls to Avoid
Do not use standard reference ranges without considering disease-specific contexts, as this can lead to misinterpretation of borderline abnormal results 1
Avoid ordering extensive imaging or invasive testing before completing basic laboratory evaluation, as this approach is inefficient and may lead to incidental findings that complicate rather than clarify the clinical picture 2
Do not neglect to screen for common comorbidities like diabetes and dyslipidemia even when they seem unrelated to presenting symptoms, as these conditions frequently coexist with other pathology 1
When to Escalate Testing
If initial laboratory testing reveals specific abnormalities, further workup should be symptom-guided and abnormality-directed rather than reflexively comprehensive 2
Endoscopic procedures should only be performed when guided by specific signs, symptoms, or laboratory abnormalities, not as routine screening in undifferentiated illness 2
Advanced imaging (CT, MRI) should be reserved for patients with localizing symptoms, abnormal physical findings, or concerning laboratory results rather than ordered empirically 2