2 Preparing Patients for Diagnostic Procedures

Match preparation to the procedure

Preparation must match the specific procedure and facility. A blood test, imaging study, biopsy, endoscopy, and examination involving sedation do not all require the same preparation. Confirm the instructions for the planned procedure rather than assuming a universal plan applies.

Assess the patient and explain the procedure

A Preprocedure assessment reviews current symptoms, medical conditions, previous procedures, and past reactions to medicines, anesthesia, or contrast media. Relevant planning factors can include diabetes; heart or lung disease; kidney or liver problems; bleeding disorders; sleep apnea; and the possibility of pregnancy.

For procedures involving sedation or anesthesia, the anesthesia team also assesses the patient’s history and physical status and plans care accordingly. Explain what the procedure involves, why it is being done, expected sensations, and relevant risks. Confirm that questions have been answered and that consent has been obtained by the responsible clinician as required.

Report new illness, worsening symptoms, or uncertainty about preparation instructions to the care team before proceeding.

Review medicines safely

A Medication review should include prescription and over-the-counter medicines, vitamins, herbal products, supplements, and medicines taken only occasionally. Ask about doses and the time of the last dose when relevant.

Some medicines can affect bleeding, blood pressure, blood glucose, sedation, or test results. The procedural team may provide individualized instructions about anticoagulants, antiplatelet drugs, insulin or other diabetes medicines, and supplements. Patients should not stop, skip, or change a medicine unless the prescribing or procedural team tells them to. If instructions are unclear, especially for medicines that must be taken regularly, contact the team before the procedure.

Document allergies and previous reactions

Ask what substance caused a reaction and what happened. Record the reaction, its severity, and any treatment rather than recording only the word “allergy.” When possible, distinguish an allergic reaction from an expected side effect or intolerance.

Ask specifically about previous reactions to anesthetic medicines, antibiotics, latex, skin cleansers, adhesives, and imaging contrast when these may be used. A previous reaction to the same class of Contrast media is important before contrast-enhanced imaging. Other allergies should also be documented, but do not automatically mean contrast cannot be given. The radiology team uses the history and planned examination to decide what precautions are appropriate.

Follow fasting and fluid instructions

Fasting instructions depend on the test and on whether sedation or anesthesia will be used. Some laboratory tests require fasting, while many do not. Sedation and anesthesia may require fasting to reduce the chance that stomach contents enter the lungs.

Do not assume that “nothing after midnight” applies to every procedure or that water is always permitted. Follow the specific instructions from the care team. Tell the team if the patient ate or drank during a fasting period or is unsure when fasting began. The team can assess whether it is safe to proceed, change the plan, or reschedule; do not conceal a missed instruction.

If fasting may affect medicines, particularly diabetes treatment, ask for a specific medication and glucose-monitoring plan.

Use targeted tests and review results

Order or review Laboratory tests when indicated by the patient’s health, symptoms, medicines, and planned procedure—not as an automatic panel for every patient. Depending on the situation, tests may include blood counts, electrolytes, kidney function, coagulation studies, pregnancy testing, or other targeted tests.

Kidney function may be relevant before certain contrast examinations. Coagulation status may matter when bleeding risk is a concern or when a procedure is near the spinal canal. The responsible clinician decides which tests are needed and whether existing results are adequate.

Review an unexpected result, a missing required result, or a change in the patient’s condition before proceeding. Do not interpret a laboratory result in isolation from the patient’s history and planned procedure.

Give instructions and complete final checks

Give instructions in clear, accessible language and confirm that the patient understands them. Depending on the procedure, instructions may cover:

• When to stop eating and drinking, and which medicines to take or hold.

• Bowel preparation, hydration, skin cleansing, or other procedure-specific steps.

• Whether to bring medication information, identification, or relevant records.

• What to expect during and immediately after the test, including whom to contact with concerns.

• Arranging a responsible adult and transportation home when sedation or the procedure makes driving unsafe.

Before starting, verify the patient’s identity and planned procedure. Review relevant allergies and medicines, confirm required preparation and test results, and ask about new symptoms or possible pregnancy when relevant. If a key safety detail is uncertain, pause and clarify it with the appropriate clinician.