Patient Identification, Clinical Screening & Pregnancy Protocols

Confirm the patient, order and clinical question

Use the required independent identifiers to match the patient to the order and record. A room number or physical location is not an adequate identifier. Review the requested examination, indication, anatomical site, contrast route and relevant clinical information. If an order and the clinical question conflict—for example, an unenhanced routine scan requested for a vascular emergency—obtain clarification through the responsible clinician before proceeding.

Screening is not simply a checklist of reasons to refuse imaging. It identifies circumstances that change preparation, technique, monitoring or the benefit-risk decision. Record the information and communicate meaningful findings so that the authorized team can choose an appropriate plan. A technically successful scan of the wrong patient or wrong region has failed the basic identity and indication task.

Prior reactions and current medications

Ask what happened during a previous contrast administration, which class of agent was used, how severe the event was and what treatment was needed. A prior allergic-like reaction to the same class is a meaningful risk factor; nonspecific warmth or isolated nausea may represent a physiologic effect instead. Clarify the history rather than recording every unpleasant sensation as anaphylaxis.

Seafood, shellfish or povidone-iodine allergy does not create a special “iodine allergy” that uniquely predicts iodinated contrast reactions. Asthma and unrelated allergies may increase risk, but do not alone require routine premedication. A prior severe same-class reaction needs an individualized plan, potentially considering another examination, an agent change and appropriate preparation. No test dose or premedication guarantees that a reaction will not occur.

Review metformin, anticoagulants, cardiac medications and other drugs relevant to the examination. Metformin management depends on renal function, AKI and route-specific concerns; it is not automatically held for every IV contrast CT. Cardiac CTA medications and procedures requiring puncture have additional medication checks under their respective protocols. Do not independently discontinue therapy from a generalized study-guide table.

Renal assessment and laboratory interpretation

Use the department's risk-based process to determine whether a renal measurement is needed and whether it is recent enough for the patient's condition. Estimated glomerular filtration rate (eGFR) helps assess stable kidney function, but it is less reliable when creatinine is changing during acute kidney injury (AKI). Ask about recent illness, renal disease and other relevant history rather than treating one old laboratory result as permanent clearance.

Stable eGFR at least 30 mL/min/1.73 m² without AKI does not automatically require prophylactic IV hydration under ACR guidance. AKI or eGFR below 30 warrants the responsible team's benefit-risk assessment and prevention plan when appropriate. There is no universal creatinine value that independently forbids all necessary contrast imaging. Document the reviewed result and decision, including any instruction to modify the plan.

Pregnancy screening and justification

Assess pregnancy possibility according to the examination's radiation risk and institutional policy. Menstrual history, patient-reported possibility and testing may be relevant. Do not invent one mandatory age interval or assume that a scan within ten days of menstruation eliminates pregnancy. A negative test can be limited by timing and should be interpreted with the clinical context.

If pregnancy is known or suspected, notify the responsible clinician so that the indication, alternatives, scan range and technique can be assessed. Necessary CT is not automatically forbidden. Fetal exposure depends strongly on whether the fetus is in the direct beam and on the actual acquisition. A head examination differs from an abdominopelvic examination; one fixed fetal-dose number cannot describe every scanner and protocol.

Avoid unnecessary phases and repeats, preserve the required information and use physicist assistance for a dose estimate when needed. Radiation-risk counseling should use the actual circumstances and avoid claiming either zero risk or inevitable harm. The responsible clinical team makes the justification decision and documents it appropriately.

Iodinated contrast in pregnancy and breastfeeding

Iodinated contrast crosses the placenta. Use it when the clinical benefit justifies administration rather than withholding it solely because pregnancy is present. Follow current guidance and the patient's clinical pathway regarding neonatal care; do not invent a universal additional test requirement from a technical guide.

After maternal IV iodinated contrast, less than 1% of the maternal dose enters breast milk and less than 1% of that ingested amount is absorbed by the infant. Thus the estimated infant systemic exposure is less than 0.01% of the maternal administered dose, not 0.01 as a fraction of the full dose. ACR guidance supports continued breastfeeding. Discuss a parent's preference with the responsible clinician instead of instructing every patient to discard milk for 24–48 hours.

Practical contraindications and positioning limitations

Assess whether the patient can lie safely, maintain the necessary airway, tolerate the scan duration and follow instructions. Check body habitus against the couch's rated load and gantry clearance. Preserve trauma immobilization and relevant lines, drains or oxygen. A limitation may require a modified position, shorter protocol, additional support or another imaging plan.

Close the loop in the record

Record clinically relevant findings, laboratory information, notifications and the final authorized plan. Protect confidentiality when discussing sensitive history; do not announce pregnancy possibility or a diagnosis in a public waiting area. Screening is complete when identified issues have an accountable decision and the acquisition matches that decision, not merely when every field has been clicked.

Reference: ACR contrast manual, FDA radiation-risk guidance.