Capillary Refill Test

Original Editor - Anas Mohamed Top Contributors -

Definition[edit | edit source]

The Capillary refill test (CRT) is a rapid test used for assessing the blood flow through peripheral tissues. It's a quick test performed on the nail beds to monitor the amount of blood flow to tissues and dehydration. [1] The CRT measures the efficacity of the vascular system of hands and feet as they are far from the heart. [2]

Alternative names[edit | edit source]

The Capillary refill test is also called: [1]

  • Digit blood flow test
  • Capillary refill time
  • Capillary nail refill test

Procedure[edit | edit source]

The following steps have to be followed when doing the test: [3]

Step1. Remove finger rings and nail polish.

Step2. The therapist compresses the nail bed until it turns white and records the time taken for the color to return to the nail bed.

Step3. It normally takes 3 seconds or less. When it takes longer, arterial insufficiency is suspected.

Step4. Always compare to the normal side of the hand or fingers.

Although the CRT is used in both children and adults [4], there is less literature about its use among adults [1] as well as very little research information about its validity. [5]

  1. Interpretation of Results
  1. Normal Results

The CRT is largely recommended in the routine of unwell patients and should last less < 2 seconds. If the color is pink after there is no more pressure; it indicates a good blood flow to the finger.t It's part of the assessment of patients seriously ill. [4]

2. Abnormal Results

A CRT> 2 seconds or prolonged CRT is suggestive of an early sign of shock. [5]

Several other factors can affect the CRT measurement and therefore its results. They may include: [4] [5]

  • Peripheral vascular disease
  • Hypothermia
  • Cold ambient temperature
  • Poor lighting
  • Old age
  • Pressure application
  • Intra and interobserver reliability

The ABCDE approach used by nurses to assess and treat severely ill patients has 5 components namely: Airway, Breathing, Circulation, Disability, and Exposure. Although the CRT represents a big part of the Circulation during this assessment, a thorough examination should be done and should include:[5]

  • Pulse rate
  • Pulse volume
  • Blood pressure
  • Level of consciousness
  • Skin color/ temperature/texture
  • Urine output
  • as well as other clinical findings of the ABCDE approach/assessment

The ABCDE assessment looks for life-threatening conditions and therefore brings lifesaving interventions to critically ill patients. [6] .

References[edit | edit source]

  1. 1.0 1.1 1.2 Capillary nail refill test. Available from: (Accessed 24 October 2020)
  2. Capillary nail refill test. Available from: (last Accessed 25 October 2020)
  3. David J. Magee. Orthopedic Physical Assessment. 6th edition. Elsevier. 2014.
  4. 4.0 4.1 4.2 Pickard A, Karlen W, Ansermino JM. Capillary refill time: is it still a useful clinical sign?. Anesthesia & Analgesia. 2011 Jul 1;113(1):120-3. 
  5. 5.0 5.1 5.2 5.3 How to measure capillary refill time in patients who are acutely ill. Available from: (Accessed 24 October 2020)
  6. The ABCDE Approach for Medical students. Available from: ( Accessed 28 October 2020)
  7. Paramedics Course -Capillary Refill Time - Australian Paramedical College. Paramedical College. Available from:
  8. Capillary Refill Test. Dr. Borst's Occupational Therapy Classroom. Available from: