Best Practices: Clinical Assessment of Pain Intensity

Pain is an individually experienced phenomenon producing a widely different sensory effect that cannot be easily measured by objective examination.  The importance of pain assessment however has led to the development of a number of validated clinical tools designed to measure the self-expression of a patient’s pain level.  These self-reporting tools are the gold standard of pain assessment and can be used to evaluate the severity of the pain, its effect on physical functions and the effect of treatment when measured serially.

Among the most commonly used and well known are the Visual Analog Scale (VAS) and Numeric Pain Scale (NPS).

The VAS uses an unmarked horizontal line of precisely 100mm on which the patient marks their pain level ranging from no pain to most pain. VAS

The NPS uses a horizontal line with a segmented scale of numbers marked from 0-10 where the patient is asked to place their mark rating their pain. The length of the line is not essential for this scale.NPS

These tools can be expanded to include multiple measures of pain, e.g. Quadruple VAS (QVAS) where pain is rated 1) present 2) average or typical 3) at worst 4) at best.

Another pain measuring tool that is often combined with a numeric pain scale and physical or functional capacity is the pictographic or Faces Pain Scale (FPS). This employs pictures of faces expressing levels of pain from no pain to most pain and was originally developed to assess the intensity of children’s pain. The CHP Group has developed a vertical pictographic FPS with an associated numeric pain level, verbal description of pain, physical capacity, and Spanish language translation. Click here to download the new CHP FPS

These scales can also be adapted to other physical symptoms, e.g. discomfort, stiffness, perception of breathing capacity for asthmatics.

When implementing these instruments, an initial evaluation of a new patient or existing patient with a new problem is appropriate and at intervals thereafter consistent with the type of condition and the patient’s response to care. For example, a more acute condition would likely see more rapid progress and re-measuring in days is reasonable compared to a chronic condition where change may occur more slowly and re-measuring in weeks may be more appropriate. Similarly, these numbers can be used to set treatment goals, e.g. reduce pain by 50% in 2 weeks.