By January 20, 2013 2 Comments Read More →

Red Flags

I reviewed a recent article by Henschke et al (2009) in relation to Red Flags titled:

Prevalence of and Screening for Serious Spinal Pathology in Patients Presenting to Primary Care Settings With Acute Low Back Pain

The purpose of this study being to determine prevalence of serious pathology in patients presenting with acute lower back pain to a primary care setting.

1,172 patients were recruited for the study and assessed via 25 red flag questions (as per the following table). The answers to these questions were used to assist with diagnosis, and subsequent referral, of patients with suspected red flag cases. Follow-up screening to ascertain any development/change in red flag diagnosis (i.e. any difference in the answers to the questions) occurred at 6 weeks, 3 months and 12 months after the initial consultation.


Results over the 12 months being:

  • 11 cases (0.9%) of “red flags” were identified.
    • 5 of these were identified at the initial consultation
    • Most common red flag was vertebral fracture.
  • Most patients (80.4%) had at least one positive answer to the above checklist, but obviously only the very small amount mentioned above had an actual red flag diagnosis.

Conclusions/Discussion by Henschke et al:

  • Serious/Red Flag pathology is rare in patients presenting to primary care providers.
  • Some red flag questions have very high false positive rates, indicating that when used in isolation they have little diagnostic value in the primary care setting. Examples being:
    • 5 of the 11 red flags for inflammatory arthritides had a false positive of > 10%. These being:
      • Tried bed rest but no relief
      • Insidious onset
      • Morning back stiffness lasting > 30 mins.
      • Family history of arthritis or osteoporosis
      • Pain improves with exercise
    • 3 of the 8 red flags for cancer had a false positive rate of > 10%. These being:
      • Age of onset < 20 years or > 55 years of age
      • Tried bed rest but no relief
      • Insidious onset
  • To help patients identify/diagnose vertebral fracture a diagnostic rule (based on the checklist above) was developed which is summarised in the following table:


My conclusions from the above research being that:

  • I would agree that red flags are uncommon in clinical practice. 
  • Having said that I think it integral that we still regularly screen all patients for red flags.
  • The checklist from Henscke et al (2009) included above, in my opinion, is a very useful list of typical questions we should screen for with our patients.
  • Whilst there are false positives with a number of the questions, and it is not uncommon for patients to present with at least 1 “red flag” on the checklist that don’t have a red flag diagnosis, I still think it important that if we have even a slight “index of suspicion” that we refer for further assessment/investigation.


Henschke N, Maher CG, Refshauge KM, Herbert RD, Cumming RG, Bleasel J, York J, Das A, McAuley JH. Prevalence of and screening for serious spinal pathology in patients presenting to primary care settings with acute low back pain. Arthritis Rheum. 2009 Oct;60(10):3072-80.

Posted in: Clinical Reasoning

About the Author:

Mark is a Specialist Musculoskeletal Physiotherapist who consults at both Insight Physiotherapy and Pain Options, in Perth, Western Australia. He specialises in the assessment and management of persistent/chronic musculoskeletal pain. In addition to his clinical role he maintains regular involvement in education of the profession having held a Teaching Fellow position at the University of Western Australia for 10 years and regularly presenting at courses and seminars through the Australian Physiotherapy Association and private education sector. Mark is also a Facilitator for the Australian College of Physiotherapists Specialisation Training Program and a Sessional Academic at Curtin University. The views expressed on this blog are his own.

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