Capillary Refill Time

What Is Capillary Refill Time?

Capillary refill time (CRT) is a quick bedside test of peripheral perfusion, performed by pressing on a nail bed (or the sole of the foot/palm in infants) until it blanches white, then releasing and timing how long it takes for normal color to return. A normal capillary refill is under 2 seconds; a delayed refill (over 2–3 seconds) suggests poor peripheral perfusion, which can indicate shock, dehydration, hypothermia, or a local circulatory problem in the limb being tested. It's one of the fastest, no-equipment perfusion checks available in the field, and is a core component of the pediatric assessment triangle and START/SALT mass casualty triage, where CRT (or radial pulse presence in adults) helps quickly sort patients by perfusion status.

Why Capillary Refill Time Matters on the Fireground

CRT gives an immediate read on perfusion status without needing a blood pressure cuff, which is especially valuable in pediatric patients, mass casualty triage, and low-light or noisy environments where other assessments are harder to perform quickly. It's not perfect on its own — cold ambient temperature, poor lighting, and patient age all affect accuracy — but combined with skin color, temperature, and mental status, it's a fast way to flag a patient who may be compensating for shock before blood pressure drops.

Relevant NFPA Standards

• NFPA 455: Standard for Emergency Medical Services (EMS)
• NREMT Standards: National Registry of Emergency Medical Technicians EMT Practice Standards

Field Procedures & Tactical Steps

1. Select an appropriate testing site — typically a fingernail bed in adults and older children, or the sole of the foot or palm in infants.
2. Press firmly on the nail bed or skin until it blanches white, then release.
3. Count the seconds until normal color returns, using a watch or mental count for accuracy.
4. Interpret a refill time under 2 seconds as normal and over 2–3 seconds as delayed, indicating possible poor perfusion.
5. Correlate the finding with skin color, temperature, mental status, and other vital signs rather than relying on CRT alone to determine shock status.

Common Context & Application

Checked during the circulation assessment of a primary survey, especially in pediatric patients, trauma patients, and mass casualty triage, where it offers a fast, equipment-free way to screen for poor perfusion before more detailed vital signs are obtained.

Frequently Asked Questions about Capillary Refill Time