From the Guidelines
A comprehensive initial diagnostic evaluation for a patient with unknown symptoms should include a detailed medical history, physical examination, and basic laboratory tests such as complete blood count, urinalysis, and serum electrolytes, as well as a 12-lead electrocardiogram and chest radiograph. The initial assessment should prioritize the patient's ability to perform daily activities and include an evaluation of volume status, orthostatic blood pressure changes, and calculation of body mass index 1. A systematic approach to diagnosis helps establish a differential diagnosis while minimizing unnecessary tests.
Initial Evaluation
The evaluation should cover:
- Detailed medical history, including onset, duration, and progression of symptoms, past medical conditions, medications, allergies, family history, and social habits
- Physical examination, including vital signs and a systematic assessment of all body systems
- Basic laboratory tests, such as:
- Complete blood count to assess for infection, anemia, or blood disorders
- Urinalysis to screen for kidney disease, infection, or diabetes
- Serum electrolytes, including calcium and magnesium, to evaluate electrolyte balance
- Blood urea nitrogen and serum creatinine to assess kidney function
- Fasting blood glucose and lipid profile to evaluate glucose and lipid metabolism
- Additional first-line tests, such as:
- 12-lead electrocardiogram to evaluate cardiac function 1
- Chest radiograph to assess lung and cardiac structure
Specialized Testing
Specialized testing, such as two-dimensional echocardiography with Doppler or coronary arteriography, should be ordered based on the clinical presentation and suspicion of specific conditions, such as heart failure or coronary artery disease 1.
Clinical Judgment
Clinical judgment is essential in determining the appropriate diagnostic tests and evaluations for a patient with unknown symptoms, and tests should be ordered judiciously based on the clinical picture rather than as a shotgun approach 1.
From the Research
Initial Diagnostic Tests
The following tests are suggested for initial diagnosis:
- Complete Blood Count (CBC) 2, 3: This test evaluates the total numbers and characteristics of cell components in the blood, including red blood cell count, hemoglobin, hematocrit, white blood cell count and differential, and platelet count.
- Liver Function Tests (LFTs) 4: These tests are used to evaluate the liver's condition and can help identify any abnormalities.
Evaluations
Consider the following evaluations:
- Physiologic basis and clinical usage of the complete blood count 2: Understanding the function, life cycle, and physiology of the various cell components can aid in difficult diagnoses and in monitoring treatments for hematologic disorders and other medical problems.
- Relationship between CBC components and diseases 3: White blood cell (WBC), neutrophil-to-lymphocyte ratio (NLR), hemoglobin (Hb), mean corpuscular volume (MCV), red cell distribution width (RDW), platelet count, mean platelet volume (MPV), and platelet-to-lymphocyte ratio (PLR) are useful markers to predict cardiovascular disease (CVD) and metabolic diseases.
Limitations
Note the following limitations:
- Low yield of preoperative screening tests in patients with clinically node-negative breast cancer 4: Routine preoperative determination of CBC, LFTs, and chest X-ray (CXR) is not warranted, and staging studies should be limited to patients with signs or symptoms.