Is there a chart showing which pre‑operative laboratory tests are required for adult surgical patients based on routine testing, patient‑specific risk factors, and the type of surgery?

Preoperative Laboratory Testing: Risk-Based Algorithm

Preoperative laboratory testing should be based on patient-specific risk factors, surgical risk level, and whether results will change perioperative management—routine testing for all patients is not recommended and wastes resources. 1, 2

Risk Stratification Framework

Use clinical risk indices (Lee Risk Index or NSQIP model) to stratify cardiac risk, then match testing to the combination of patient risk factors and surgical risk level. 3, 1

Patient Risk Factors to Identify:

• Cardiovascular: Known coronary artery disease, heart failure, cerebrovascular disease, structural heart disease 3, 1
• Metabolic: Diabetes mellitus, chronic kidney disease (eGFR <60), liver disease 3, 1
• Medications: Diuretics, ACE inhibitors, ARBs, anticoagulants, NSAIDs, digoxin 1
• Hematologic: Personal or family history of bleeding disorders, anemia history 3, 1
• Functional capacity: Inability to climb 2 flights of stairs or achieve <4 METs 3, 4

Surgical Risk Categories:

• Low-risk: Cataract, endoscopy, superficial procedures 3, 1
• Intermediate-risk: Orthopedic, intra-abdominal, head/neck surgery 3, 1
• High-risk: Vascular, major thoracic, cardiovascular surgery 3, 2

Testing Algorithm by Patient and Surgical Risk

Healthy Patients (ASA Class 1) + Low-Risk Surgery

No routine testing required. 1, 4

• No ECG 1, 4
• No CBC 1, 4
• No chemistry panel 4
• No coagulation studies 3, 4
• No chest X-ray 1, 2
• Exception: Consider pregnancy testing for females of childbearing age 3, 4

Evidence strength: Routine testing in this population identifies abnormalities in only 0.8-22% of cases, with management changes occurring in merely 1.1-4% of abnormal results. 3, 5 Studies show no association between testing and reduced complications in low-risk patients. 6, 5

Patients with Risk Factors + Intermediate/High-Risk Surgery

Electrocardiogram (ECG)

Order for:

• Any patient with cardiovascular risk factors (coronary disease, heart failure, diabetes, renal impairment, cerebrovascular disease) undergoing intermediate or high-risk surgery 3, 1
• All patients undergoing vascular surgery with ≥1 risk factor 3
• Patients with known cardiovascular disease undergoing intermediate-risk procedures 3

Do NOT order for:

• Asymptomatic patients without risk factors undergoing low-risk surgery 3, 1
• Patients with good functional capacity (≥4 METs) and no symptoms, even with risk factors 3, 4

Complete Blood Count (CBC)

Order for:

• All cardiovascular surgery and procedures with anticipated significant blood loss 1, 2
• Liver disease, hematologic disorders, or history of anemia 1, 2
• Chronic kidney disease (eGFR <60) 1

Electrolytes and Creatinine

Order for:

• Patients taking diuretics, ACE inhibitors, ARBs, NSAIDs, or digoxin 1
• Chronic kidney disease, hypertension, heart failure, complicated diabetes, or liver disease 1
• All neurosurgery and cardiovascular surgery 1, 2

Coagulation Studies (PT/PTT/Platelets)

Order for:

• Personal or family history of bleeding disorders 3, 1
• Liver disease or conditions predisposing to coagulopathy 3, 1
• Current anticoagulant use 1
• NOT for: Routine screening without bleeding history 3, 2

Glucose/Hemoglobin A1C

Order for:

• High risk of undiagnosed diabetes (random glucose) 1
• Known diabetes ONLY if results would change perioperative management (A1C) 1

Caveat: Occult diabetes prevalence in presurgical populations is only 0.5%, making universal screening unjustified. 1

Chest Radiography

Order for:

• New or unstable cardiopulmonary signs or symptoms 1, 2
• Patients at risk of postoperative pulmonary complications IF results would change management 1, 2
• NOT for: Routine screening in asymptomatic patients, even before major surgery 2

Urinalysis

Order for:

• Urologic procedures 1
• Implantation of foreign material (prosthetic joints, heart valves) 1
• NOT for: Routine screening 1

Special Population Considerations

Patients with Moderate Renal Impairment (eGFR 30-59)

• CBC (anemia risk >50% when eGFR <30) 1
• Calcium, phosphate, PTH, alkaline phosphatase if eGFR <45 1
• Electrolytes and creatinine 1

Patients Under 45 Years Without Medical History

• No routine studies for low-risk surgery 4
• Apply same risk-based algorithm as above for intermediate/high-risk procedures 4

Major Surgery (Intermediate/High-Risk Patients)

• FBC, ECG, renal function, coagulation profile 2
• Assessment must occur prior to day of surgery for ASA class 3 patients 2

Critical Pitfalls to Avoid

Do not order tests "just to be safe" or because "it's always been done." 4 This approach leads to:

• Estimated $18 billion annual waste in the U.S. 7
• False positives requiring unnecessary follow-up
• Potential surgical delays without clinical benefit 8, 5

Do not use arbitrary age cutoffs. Age alone is not an indication for testing—functional capacity and comorbidities matter more. 3, 4

Only order tests that would alter perioperative care. 3, 1, 2 If an abnormal result wouldn't change your management, don't order the test.

When to Consider Additional Cardiac Testing

For patients with poor functional capacity (<4 METs) and ≥3 clinical risk factors undergoing vascular surgery, consider noninvasive stress testing if it will change management. 3 However, patients with good functional capacity (≥4 METs) can generally proceed without further testing. 3, 4

Biomarkers (BNP/troponin): Consider in high-risk patients before and 48-72 hours after major surgery for prognostic information, but routine biomarker sampling for all patients is not recommended. 3, 1