What is the recommended approach for preoperative testing?

Preoperative Testing Should Be Selective, Not Routine

Preoperative testing must be driven by the patient's clinical history, physical examination findings, comorbidities, and the specific surgical risk—not by protocol or routine ordering. 1, 2

Core Principle: History and Physical Examination Drive Testing Decisions

The fundamental approach is straightforward: order tests only when findings from history or examination suggest underlying disease, when specific medications create risk, or when the surgical procedure itself demands baseline values. 1, 2 Routine batteries of tests do not change perioperative management, unnecessarily delay surgery, increase costs, and may trigger cascades of follow-up testing that rarely benefit patients. 1, 3

Algorithmic Approach by Test Type

Electrocardiography (ECG)

Order ECG if:

• Active cardiovascular symptoms exist (chest pain, dyspnea, palpitations, syncope) 1, 2
• High-risk surgery is planned (vascular, major intra-thoracic, intra-abdominal procedures) 2
• Intermediate-risk surgery is planned AND patient has ≥1 cardiac risk factor: known coronary disease, structural heart disease, heart failure history, cerebrovascular disease, diabetes mellitus, or renal impairment 2, 4

Do NOT order ECG if:

• Low-risk surgery (cataract, endoscopy, superficial procedures) in asymptomatic patients 1, 2
• Patient has good functional capacity (≥4 METs—can climb 2 flights of stairs without symptoms) regardless of age 2, 4

Chest Radiography

Order chest X-ray if:

• New or unstable cardiopulmonary symptoms (dyspnea, cough, chest pain) 1, 2
• Risk factors for postoperative pulmonary complications exist AND results would alter management (e.g., optimization of COPD, heart failure treatment) 1, 2

Do NOT order chest X-ray:

• Routinely in asymptomatic, otherwise healthy patients 2

Complete Blood Count (CBC)

Order CBC if:

• History suggests anemia (fatigue, known blood loss, menorrhagia, GI bleeding) 1, 2
• Diseases increasing anemia risk (liver disease, hematologic disorders, chronic kidney disease) 2
• Significant perioperative blood loss anticipated (major orthopedic, vascular, oncologic surgery) 1, 2
• Cardiovascular surgery planned 2

Do NOT order CBC:

• Routinely in healthy patients undergoing minor procedures 1

Electrolytes and Creatinine

Order electrolyte panel and creatinine if:

• Patient takes diuretics, ACE inhibitors, ARBs, NSAIDs, or digoxin 1, 2
• Hypertension, heart failure, chronic kidney disease, complicated diabetes, or liver disease present 1, 2
• Neurosurgery or cardiovascular surgery planned 1, 2

Do NOT order:

• Based on age alone (the outdated "age >40 years" rule should be abandoned) 1
• In healthy patients on no relevant medications 1

Glucose Testing

Order random glucose if:

• Very high risk of undiagnosed diabetes based on obesity, family history, symptoms of polyuria/polydipsia 1, 2

Order A1C if:

• Known diabetes AND the result would change perioperative management (e.g., considering surgery delay if A1C >8-9%) 1, 2

Do NOT order:

• Random glucose routinely in patients with well-controlled known diabetes (reflects only past few hours, rarely changes management) 1
• Universal screening (occult diabetes prevalence is only 0.5% in presurgical populations) 1, 2

Coagulation Studies (PT/PTT/Platelets)

Order coagulation testing if:

• Patient takes anticoagulants (warfarin, heparin, DOACs) 1, 2
• History of spontaneous bruising, excessive surgical bleeding, or family history of heritable coagulopathy 1
• Liver disease or hematologic disorders present 1, 2

Do NOT order:

• Indiscriminately or routinely (inherited coagulopathies are rare, and routine tests may be normal even in von Willebrand disease) 1, 2

Urinalysis

Order urinalysis if:

• Invasive urologic procedures planned 1, 2
• Implantation of foreign material (prosthetic joint, heart valve) 1, 2

Do NOT order:

• Routinely (abnormalities found in up to 34% but change management <14% of the time, with complications <1%) 1, 2

Special Population: Cataract Surgery

Patients in their usual state of health undergoing cataract surgery require NO preoperative testing. 1, 2 This is supported by high-quality evidence (Level A) and represents one of the clearest recommendations in preoperative medicine. 1

Critical Pitfalls to Avoid

• Age-based testing protocols are obsolete. Do not order tests simply because a patient is over 40,50, or 65 years old without clinical indication. 1, 2
• Avoid "panel" ordering. Each test should have a specific clinical justification. 3, 5
• Do not delay surgery for mildly abnormal results that don't change management. The goal is optimization, not perfection. 3
• Functional capacity assessment is more valuable than age. A 75-year-old who walks 2 miles daily needs less testing than a sedentary 50-year-old. 2, 4

Implementation Strategy

The most effective approach involves institutional standardization through preoperative evaluation protocols that embed these evidence-based criteria into clinical workflows, ensuring consistent application while maintaining flexibility for individual clinical judgment. 3, 6 This reduces unnecessary testing, controls costs, and improves perioperative safety without compromising outcomes. 5, 7