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Laboratory Investigations
Pre-Surgical Panel (Preoperative Investigations)
A pre-surgical panel consists of laboratory tests and diagnostic examinations performed before surgery to assess the patient's overall health, identify underlying medical conditions, and minimize potential complications related to anesthesia and surgical procedures.
🎯 Objectives of Pre-Surgical Investigations
Assess Health
Evaluate the patient's general medical condition.
Reduce Risks
Detect conditions that may influence anesthesia or surgical procedures.
Identify Infections
Recognize relevant infections and guide appropriate clinical management.
Plan Surgery
Support safe perioperative assessment and care.
🧠 Mind Map: Classification of Pre-Surgical Investigations
🩸 Blood Tests
- Complete blood count (CBC)
- Blood glucose
- Blood urea nitrogen (BUN)
- Serum creatinine
🛡️ Serological Tests
- HIV-1 and HIV-2
- Hepatitis B surface antigen (HBsAg)
🧪 Urine Examination
- Routine urinalysis
📈 Diagnostic Studies
- Chest X-ray
- Electrocardiogram (ECG)
Liver function tests • Thyroid function tests • ECG, if not already performed
1. Routine Laboratory Investigations
| Investigation | Clinical Significance |
|---|---|
| Complete Blood Count (CBC) | Detects anemia, abnormal white blood cell counts, and platelet-related abnormalities. |
| Blood Glucose | Helps identify hyperglycemia, hypoglycemia, and possible diabetes mellitus. |
| Blood Urea Nitrogen (BUN) | Provides information about renal function and hydration status. |
| Serum Creatinine | Assesses kidney function, which may affect medication and anesthesia management. |
| HIV-1 and HIV-2 Testing | Identifies HIV infection when screening is clinically indicated and applicable consent requirements are met. |
| HBsAg | Screens for current hepatitis B infection. |
| Routine Urinalysis | May detect proteinuria, glycosuria, and findings suggestive of urinary tract infection. |
2. Diagnostic Investigations
Chest X-ray
Provides information about the lungs and cardiothoracic structures. It may identify pulmonary abnormalities that could affect perioperative management.
Electrocardiogram (ECG)
Records the electrical activity of the heart and helps detect arrhythmias, conduction disturbances, and signs of myocardial ischemia.
3. Additional Investigations — Selected Cases
Additional investigations are requested according to the patient's medical history, clinical findings, and the nature of the planned surgical procedure.
Liver Function Tests (LFTs)
Indicated when liver disease or hepatic dysfunction is suspected. Results may help guide drug selection and perioperative care.
Electrocardiogram (ECG)
Particularly relevant for patients with cardiovascular disease, suggestive symptoms, or cardiac risk factors.
Thyroid Function Tests (TFTs)
Requested when thyroid dysfunction is known or suspected, as it may affect cardiovascular stability and responses to anesthesia.
🔀 Flow Diagram: Preoperative Assessment
📝 Important Clinical Notes
Exam Note: A major purpose of preoperative investigations is to identify underlying diseases and reduce preventable perioperative complications.
Infection Control: Standard precautions must be followed for every patient, regardless of HIV or hepatitis B test results. Positive findings may guide patient-specific care but do not determine whether standard precautions are used.
Clinical Practice: Not every patient requires all the listed investigations. Current preoperative assessment favors selective testing based on medical history, clinical examination, comorbidities, and surgical risk. Chest X-rays, ECGs, and HIV/HBV screening are not universally indicated.
Remember five categories: Blood Count → Blood Chemistry → Serology → Urinalysis → Diagnostic and Special Investigations.
