Pain Assessment Scales: An Overview for Pharmacists

Patients benefit when pharmacists thoroughly assess pain.

Pain affects millions of Americans every year. Whether a patient’s pain is acute or chronic, or neuropathic or inflammatory, it’s undisputed that comprehensive and methodical assessment will guide pharmacists in selecting the most appropriate therapy.

Here’s an overview of some pain assessment scales:

Numeric Rating Scale (NRS)1

I recently volunteered on an interprofessional team providing health care to underserved populations in Connecticut. Several patients presented with some type of pain as their chief complaint.

Too often, I heard student clinicians ask, “On a scale of 1 to 10, how bad is your pain?” It’s essential to stress the NRS ranges from 0 to 10, with 0 being no pain at all and 10 being the worst pain imaginable.

The NRS is preferred by patients over other rating methods because of its comprehensibility.2 Therefore, the patient’s understanding of the scale and what’s being asked is key to reporting the most valid score.

The NRS is perhaps the most convenient rating scale, requiring little time and allowing ease of verbal administration, including over the phone.

Visual Analog Scale (VAS)3

The VAS is an instrument useful for pain assessment when patients can’t quantify their pain in distinct segments. It’s continuous and can be particularly valuable when assessing pain changes in one individual.

The scale is 10 cm in length and arbitrated on either end by terms like “no pain” and “very severe pain.” Patients mark where they feel their pain is, and the administering clinician measures its distance with a ruler, linking the result with a score.

The Colored Analog Scale is a similar, reliable self-reporting tool for assessment of acute pain in children.4

Wong-Baker FACES

Although initially devised for children, this pain scale is used in patients 3 years and older.

Unlike the famous scene from an episode of Scrubs, providers don’t match the patient’s face to a face on the scale. Instead, they explain to the patient that the faces on the scale are happy because they have no pain, or sad because they have pain.

While pointing to each face, describe what it would be feeling, using phrases like “Face 0 is happy because he has no pain,” and progressing to “Face 5 is very sad because he has the worst pain possible.”

McGill Pain Questionnaire (MPQ)

All of the aforementioned scales are unidimensional instruments, assessing only pain intensity. However, the MPQ is multidimensional, delivering a more thorough evaluation of pain location, intensity, quality, pattern, and behavioral dimension.5

Awareness of parameters like pain length, triggers, and severity help convey a more thorough understanding. The most complete description possible will lead to the most beneficial treatment.

Pain Assessment Checklist for Seniors with Limited Ability to Communicate (PACSLAC)6

Pain in older adults is both underreported and undertreated.7 Reasons for this vary, but may include social barriers like caregiver attitudes or patient perceptions of pain and its associated treatments.

Even more challenging is the assessment and treatment of pain in nonverbal patients. Limited communication can result from conditions like advanced dementia, stroke, or delirium.

The PACSLAC is designed to aid providers assessing pain in those populations through 4 components:

1. Facial expression: Signs to look for include grimacing, frowning, wincing, clenching teeth, open mouth, and change in eyes (squinting, increased movements).

2. Activity/body movement: This includes fidgeting, pulling away, flinching, refusing to move, thrashing, resistance to care, clenched fists, fetal position, and rigidity.

3. Social/personality/mood: Here, providers make note of physical or verbal aggression, not wanting to be touched, irritability, or anxious/upset demeanor.

4. Other: This section observes physiological changes, eating and sleeping changes, and vocal behaviors, as well as tears, sweating, crying, and vocalization for pain (like “ouch”), and moaning/groaning.

Additional Scales

Pain can have complex etiology, and it can also be the culprit behind other conditions. Chronic pain, in particular, can disrupt other functions and further lower quality of life. Associated psychological comorbidities are sleep disturbances, depression, anxiety, and substance-related disorders.8

Patients with comorbidities may be well served by additional assessments like the Patient Health Questionnaire-9, a self-reported depression rating scale.

3 Things to Keep in Mind

  • In some cases, assessment methods can be combined. For example, patients may answer a questionnaire, label the source of their pain on a drawing of a human diagram, and exhibit observational or behavioral characteristics.
  • Absence of characteristics like the ones described in the PACSLAC doesn’t mean patients aren’t in pain. Even if they don’t physically look like they’re in pain, it may just be because they’re gotten used to its intensity.
  • Everyone has a different pain tolerance or threshold. What’s unbearable to one patient may be baseline for another.

Overall, patients benefit when providers thoroughly assess pain. Tools differ in reliability and validity, but providers’ recognition and efforts to evaluate pain can make all the difference to patients who don’t know how to express what’s troubling them.


1. Hawker GA, Mian S, Kendzerska T, French M. Measures of adult pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36 BPS), and Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP). Arthritis Care Res. 2011;63(Suppl 11):S240-S252.

2. de C Williams AC, Davies HT, Chaudury Y. Simple pain rating scales hide complex idiosyncratic meanings. Pain. 2000;85(3):457-463.

3. Gould D, Kelly D, Goldstone L, Gammon J. Examining the validity of pressure ulcer risk assessment scales: developing and using illustrated patient simulations to collect the data. J Clin Nurs. 2000;10(5):697-706.

4. Bulloch B, Garcia-Filion P, Notricia D, Bryson M, McConahay T. Reliability of the color analog scale: repeatability of scores in traumatic and nontraumatic injuries. Acad Emerg Med. 2009;16(5):465-469.

5. Ngamkham S, Vincent C, Finnegan L, Holden JE, Wang ZJ, Wilkie DJ. The McGill Pain Questionnaire as a Multidimensional Measure in People with Cancer: An Integrative Review. Pain Manag Nurs. 2012;12(1):27-51.

6. Fuchs-Lacelle S, Hadjistavropoulos T. Development and preliminary validation of the pain assessment checklist for seniors with limited ability to communicate (PACSLAC). Pain Manag Nurs. 2004;5(1):37-49.

7. Tracy B, Morrison RS. Pain management in older adults. Clin Ther. 2013;35(11):1659-1658.

8. Katzman MA, Pawluk EJ, Tsirgielis D, D’Ambrosio C, Anand L, et al. Beyond chronic pain: How best to treat psychological comorbidities. J Fam Pract. 2014;63(5):260-264.