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CLINICIAN REFERENCE

Preoperative investigation reference - principle

A useful starting question is: what clinical decision will this test change? Testing depends on the patient, procedure and intended response to an abnormal result.

Why routine test batteries are discouraged

Routine testing in low-risk patients rarely changes management. It can generate incidental minor abnormalities that lead to repeat testing, referral and cancellation without improving outcomes. Targeted testing, based on history, examination and procedure, is more likely to change care.

Indian guidance

The ISA 2022 ready reckoner addresses ASA Physical Status I–II adults undergoing elective surgery. Its recommendations vary with the investigation and surgery grade. It also gives validity periods for previous normal tests when the clinical condition has not changed. The original tables provide the recommendations within their stated scope.

Where guidance differs

NICE NG45 uses a different routine-testing framework and advises against routine preoperative chest X-rays and resting echocardiography. A clinically indicated investigation is a separate question. These recommendations do not constitute a universal test battery.

Practical application

  • Before ordering: documenting the clinical question, the result that would change management and responsibility for follow-up can make testing more useful.
  • Previous results: recent normal results may be reusable if the clinical condition has not changed, within the validity periods in the applicable guideline.
  • Coagulation tests: routine screening is generally not indicated without a clinical reason. A bleeding history, liver disease or selected anticoagulant regimens may justify targeted tests. Routine PT/INR or aPTT does not reliably quantify every anticoagulant, particularly DOACs.
  • Pregnancy testing: follows local policy and consent requirements.
  • Abnormal results: advance planning can clarify how results will be reviewed and communicated, including to the patient’s usual doctor where appropriate.
  • Institutional protocols: local protocols that incorporate the applicable guideline can reduce variation between clinicians.

ASA physical status, surgery grade and comorbidity together shape the indication. Guidance from one health system may not transfer directly to another.

Sources