Capillary Refill Time · What Is It, Interpretation, and More

Published: Apr 01, 2026

Author: Nikol Natalia Armata, MD•

Editor: Alyssa Haag, MD•

Editor: Lily Guo, MD•

Editor: Kelsey LaFayette, DNP, ARNP, FNP-C

Illustrator: Abbey Richard, MSc

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What is capillary refill time?

Capillary refill time (CRT) is a test used to assess blood flow through peripheral tissues. It measures the time needed for a distal capillary bed (i.e., fingertip) to regain its color after pressure has been applied and it loses its color (i.e., blanches). CRT is now included in the initial assessment of the circulation of critically ill patients, both adults and children, as part of the advanced cardiovascular life support (ACLS) guidelines. Individual differences in CRT may depend on the room temperature during the assessment and the patient's temperature, age, and skin tone.

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When is capillary refill time assessed?

The capillary refill test provides helpful information in various medical scenarios and has multiple indications. It is a valuable indicator for assessing the perfusion and circulatory status, particularly in emergency cases, like shock states (e.g., hypovolemic, anaphylactic, septic), where a prolonged CRT (i.e., >2 seconds) may indicate poor perfusion of the tissues. In pediatric patients, where clinical evaluation may be challenging, CRT, if prolonged, provides useful information in identifying dehydration and sepsis. Additionally, it is insightful in the initial rapid assessment of trauma patients, where CRT may be increased due to massive blood loss or vasoconstriction induced by hypothermia. Evaluation of potential peripheral vascular disease (i.e., reduced blood circulation to body parts due to narrowing or blockage of blood vessels) can also be performed using the CRT. Moreover, CRT monitoring guides resuscitative efforts and assists significantly in the evaluation of individuals’ response to fluid resuscitation interventions, where improvements in the CRT indicate enhanced tissue perfusion.

How is capillary refill time assessed?

Measuring CRT involves the visual inspection of blood returning to distal capillaries after they have been emptied by pressure application of at least 5 seconds. CRT can be measured at different sites, including nail beds, fingertips, or sternum; consistency in the site of measurement is important for accurate monitoring. The time taken for the color to return to the pressed area is measured. Usually, the color should return within 2 seconds after releasing pressure. If it takes longer than 2 seconds, it may indicate poor peripheral perfusion and potential circulatory compromise. CRT should be performed on both sides of the body and compared to each other. In neonates and the elderly, the time needed for the capillary to refill may be up to 5 seconds and 4.5 seconds, respectively. Repeating the measurement after a brief interval if CRT is prolonged can help confirm findings and assess for changes. Persistent prolongation may require further investigation and intervention depending on the suspected underlying cause.

How are capillary refill time results interpreted?

Typically, CRT is under 2 seconds when circulation is adequate in peripheral tissues. However, if CRT exceeds this threshold, it may suggest impaired peripheral circulation, potentially indicating conditions such as shock, dehydration, or hypothermia. In cases of shock, prolonged CRT can serve as an early warning sign of poor blood flow and upcoming cardiovascular collapse, necessitating immediate assessment and intervention. CRT results should always be interpreted according to each patient’s clinical presentation, including vital signs (e.g., pulse oximetry, blood pressure, temperature) and symptoms. A slightly prolonged CRT, for instance, in a well-hydrated, hemodynamically stable individual may not be as concerning as in an unresponsive patient with a recent medical history of a severe car accident.

CRT can be measured at different sites, including the nail beds, fingertips, or sternum. Consistency in the site of measurement is important for accurate monitoring. Repeating the measurement after a brief interval if CRT is prolonged can help confirm findings and assess for changes. Persistent prolongation may require further investigation and intervention depending on the suspected underlying cause.

What are the most important facts to know about capillary refill time?

Capillary refill time is a test used to evaluate the peripheral blood flow by measuring the seconds needed to regain the normal color of the extremities after pressure is applied to cause blanching. Assessing the perfusion of tissues as well as the overall circulatory status of a patient is crucial, particularly in emergencies involving shock or dehydration. Among most individuals, the CRT is less than 2 seconds. Extended CRT can be a sign of circulatory impairment and inadequate perfusion, though the patient's overall clinical presentation should be considered when interpreting the CRT. If needed, it may be important to repeat the measurement and perform CRT consistently.

Key Takeaways

Definition	Capillary refill time (CRT) is a test used to assess blood flow through peripheral tissues, by measuring the time needed for a distal capillary bed to regain its color after applying pressure.
Indications	Assessing perfusion and circulatory status in: -Emergencies (e.g., shock, trauma patients) -CRT >2 seconds → poor perfusion -Included in ACLS guidelines as initial assessment of circulation -Pediatric patients -Evaluation for peripheral vascular disease -Assessment of response to fluid resuscitation
CRT assessment	-Apply pressure to fingertip or toe for 5 seconds → measure time for color to return -Normal: color returns within 2 seconds -Neonates: up to 5 seconds may be normal -Elderly: up to 4.5 seconds may be normal ->2 seconds → poor peripheral perfusion, potential circulatory compromise -Perform on both sides → compare
Interpretation	-<2 seconds → inadequate peripheral circulation ->2 seconds → impaired peripheral circulation -May suggest shock, dehydration, hypothermia -Early warning for upcoming cardiovascular collapse -Interpretation depends on clinical presentation and recent medical history

References

Caruggi S, Rossi M, De Giacomo C, et al. Pediatric dehydration assessment at triage: Prospective study on refilling time. Pediatric Gastroenterology, Hepatology & Nutrition. 2018;21(4):278. doi:https://doi.org/10.5223/pghn.2018.21.4.278

Lamprea S, Fernández-Sarmiento J, Barrera S, Mora A, Fernández-Sarta JP, Acevedo L. Capillary refill time in sepsis: A useful and easily accessible tool for evaluating perfusion in children. Frontiers in Pediatrics. 2022;10. doi:https://doi.org/10.3389/fped.2022.1035567

Pickard A, Karlen W, Ansermino JM. Capillary refill time. Anesthesia & Analgesia. 2011;113(1):120-123. doi:https://doi.org/10.1213/ane.0b013e31821569f9