Red Flags in Physiotherapy

Only about 1% of all musculoskeletal presentations in primary care are caused by serious pathologies.¹²These include conditions such as:

• Spinal infection

• Cauda equina syndrome

• Fracture

• Malignancy³

Among these, vertebral fractures are the most common serious spinal pathology, followed by metastatic bone disease.⁴Despite their low prevalence, it is essential to consider these conditions as differential diagnoses, especially in patie

The Importance of Early Identification

Early identification of serious pathologies offers several key benefits:

Improved prognosis: Early diagnosis increases the likelihood of successful treatment and recovery.

Better treatment tolerance: Patients respond more favorably to medical and surgical interventions when the disease is identified in its early stages.

Improved outcomes Early intervention can prevent complications and functional impairment.

Maintaining quality of life: Timely management minimizes the disease’s impact on daily living.¹

Challenges in Diagnosis

Diagnosing serious pathologies can be difficult, especially in the early stages.These conditions often mimic common musculoskeletal disorders, which can delay appropriate diagnosis.As the disease progresses, systemic symptoms may appear, such as:

• Fever

• General malaise

• Unintentional weight loss¹

Although serious pathologies represent a small percentage of musculoskeletal cases in primary care, their consequences are significant.This highlights the importance of careful assessment of red flags in patients presenting with back pain or other musculoskeletal symptoms.Recognizing warning signs early ensures timely diagnosis and treatment, improving both prognosis and quality of life.

What Are Red Flags?

Red flags (RFs) are clinical signs and symptoms used to screen for serious underlying pathologies that may mimic musculoskeletal pain.⁵They are specific indicators derived from the patient’s history and physical examination, suggesting a high risk of conditions such as infection, malignancy, or fracture.⁶

Purpose and Function

Not diagnostic tools:Red flags are not designed to diagnose or predict prognosis but act as clinical prediction markers.

Primary function:To increase clinician suspicion when multiple red flags are present.⁶

The Flag System

The flag system describes different categories of clinical and psychosocial indicators:

Red flags:Indicators of possible serious pathology — such as inflammatory or neurological conditions, structural damage, infection, tumors, or systemic disease.These often require immediate investigation or surgical referral.

Other flag types:

• Orange flags: Mental health concerns

• Yellow flags: Psychosocial factors influencing pain experience

• Blue and black flags: Work-related or social barriers

For more details, see The Flag System or Louis Gifford’s Pink Flags and Tendons framework.

Red Flags in the Screening Process

Screening tools that include red flags have been developed to identify serious spinal pathologies.¹However, there is limited consensus across clinical guidelines, and specific questions may vary.⁷⁸⁹

A comprehensive review identified 163 elements considered red flags:

• 119 elements from patient history

• 44 elements from physical examination¹⁰

Controversies and Limitations

Lack of evidence: Research supporting the use of specific red flag questions is limited.⁷⁸⁹

Subjective interpretation: The sheer number of red flags and lack of standardization reduce their practical reliability.¹⁰

Clinical relevance: Despite limited evidence, red flags remain the most reliable indicators for potentially serious conditions and are fundamental in the assessment process.¹⁰

While red flags do not always provide definitive answers, they play a crucial role in determining whether a patient is suitable for conservative treatment or requires referral for further investigation.This underscores the importance of integrating red flag assessment into clinical decision-making.

Common Red Flags in Clinical Practice

Red flags are clinical indicators that suggest possible serious pathology, especially in musculoskeletal conditions such as back pain.Although widely used, their accuracy and predictive value remain debated.

Typical Red Flags

• Age over 50 years:Increased risk of vertebral fractures and malignancy.

• Symptom progression:Worsening symptoms over time may indicate a serious underlying disorder.

• Thoracic pain:Unusual presentation for mechanical back pain; may signal metastatic disease.

• History of cancer:Strongly associated with risk of spinal metastasis.

• Unexplained weight loss:Potential sign of malignancy.

• Intravenous drug use:Raises risk of spinal infection such as osteomyelitis.

• Night pain:May suggest malignancy or inflammatory disease.

• Systemic illness (fever):Can indicate infection, such as spinal abscess.

• Night sweats:Associated with systemic infection or malignancy.¹

Evidence for Red Flags

Positive red flags and related pathologies:

• Recent trauma in patients over 50: Strongly linked to vertebral fractures.⁷

• Previous or suspected cancer: High diagnostic accuracy for detecting malignancy.¹¹

General challenges:

• Red flags generally have low diagnostic accuracy.⁷

• There is no universal agreement on which red flags should be used or when to act.¹²

Criticism and Clinical Challenges

According to Cook et al., four key factors explain why red flag screening is not always successful:⁸

1. Inability to rule out serious pathology: Red flags may indicate risk, but their absence does not exclude severe conditions.They have low negative likelihood ratios, meaning a negative test does not guarantee safety.

2. Variability in definitions: Large differences in how red flags are defined limit both research consistency and clinical application.

3. Overuse of diagnostic testing: Many guidelines recommend extensive testing even if only one red flag is present —however, at least 80% of patients show one or more red flags, making over-testing a real concern.¹

4. Misconception about screening: Red flags are not pre-symptomatic screening tools; rather, they are used after symptom presentation to guide clinical management.

Clinical Relevance

Although red flags are not always reliable indicators, they remain an essential part of clinical reasoning.They assist clinicians in deciding whether to pursue further diagnostics or specialist referral.Proper use requires careful clinical judgment combined with an understanding of the patient’s overall history and context.Despite limitations, red flags are still fundamental for early detection of potentially serious pathologies.

Alternative Clinical Approaches: Improving Red Flag Screening

Despite their limitations, clinicians are still encouraged to use red flags as part of their assessment to identify serious conditions.Recent research has emphasized an alternative, context-based framework for red flag screening.¹⁰

Contextual Approach

A key element of this framework is to understand the entire patient history and ask questions that provide context for the red flag responses.¹

Example: History of Cancer

It is important to determine the primary cancer site, as certain cancers have a higher likelihood of spinal metastasis.The five most common cancers that spread to the spine are:Breast, Prostate, Lung, Kidney, and Thyroid.¹Suspicion of metastasis should lead to more comprehensive investigation.

Example: Unexplained Weight Loss

To assess risk properly, the clinician should explore:

• Is the patient dieting or exercising more?

• Has the patient started new medication affecting appetite?

• Is pain limiting food intake?¹

Example: Night Pain

Night pain is common, but its quality matters:Patients who can return to sleep are less concerning than those who must sit upright or walk to relieve pain.¹

This level of detail allows clinicians to better assess the seriousness of symptoms.

Framework for Red Flag Evaluation

This modern framework integrates context, symptoms, and overall health status to support early identification of serious pathology while minimizing unnecessary investigations.

1. Assessing Concern Level

• Context-based reasoning: Clinicians should avoid relying on a single red flag and instead interpret findings within the patient’s overall presentation and comorbidities.¹³

• Symptom progression: Monitor how symptoms evolve and whether they match the expected course of a benign or serious condition.

2. Decision-Making Process

• No concern: Begin treatment immediately.

• Moderate concern: Begin a trial of care and re-evaluate the patient closely over time.

• High concern:

  • Emergency: e.g. suspected cauda equina syndrome → immediate action.

  • Urgent but not emergent: e.g. possible metastasis → referral within days.¹³

3. Treatment Pathway

A flexible framework allows patients to move between care pathways as symptoms evolve.Ongoing clinical monitoring ensures that treatment is continuously adapted.

4. Key Principles Summary

• Early identification improves outcomes and preserves quality of life.

• Serious pathologies may mimic benign musculoskeletal conditions.

• Context matters: Red flags must be interpreted within the patient’s full clinical picture.

• Regular re-evaluation is essential at every visit.

• Appropriate referral ensures timely and effective management.

Clinical Significance

This framework provides clinicians with a structured yet flexible method for identifying serious pathologies early.By combining contextual reasoning, ongoing reassessment, and dynamic monitoring, physiotherapists can more accurately tailor treatment and improve patient outcomes.

Sources

1. Finucane L. An Introduction to Red Flags in Serious Pathology Course. Plus, 2020.

2.  Melman A, Maher CG, Needs C, Machado GC. Many people admitted to hospital with a provisional diagnosis of nonserious back pain are subsequently found to have serious pathology as the underlying cause. Clin Rheumatol. 2022 Jun;41(6):1867-71.

3.  Chu EC, Trager RJ. Prevalence of serious pathology among adults with low back pain presenting for chiropractic care: a retrospective chart review of integrated clinics in Hong Kong. Med Sci Monit. 2022 Sep 27;28:e938042.

4.  Finucane L, Greenhalgh S, Selfe J. Which red flags aid the early detection of metastatic bone disease in back pain? Physiotherapy Practice and Research. 2017;38(2): 73-77.

5.  Maselli F, Palladino M, Barbari V, Storari L, Rossettini G, Testa M. The diagnostic value of Red Flags in thoracolumbar pain: a systematic review. Disabil Rehabil. 2022 Apr;44(8):1190-1206.

6. Finucane LM, Downie A, Mercer C, Greenhalgh SM, Boissonnault WG, Pool-Goudzwaard AL et al. International Framework for Red Flags for Potential Serious Spinal Pathologies. J Orthop Sports Phys Ther. 2020;50(7):350-372.

7. Premkumar A, Godfrey W, Gottschalk MB, Boden SD. Red Flags for Low Back Pain Are Not Always Really Red. J Bone Jt Surg. 2018;100(5):368–74.

8.  Cook CE, George S Z, Reiman M P. Red flag screening for low back pain: nothing to see here, move along: a narrative review. British Journal of Sports Medicine. 2018;52: 493–496.

9.  Budtz CR, Rønn-Smidt H, Thomsen JNL, Hansen RP, Christiansen DH. Primary care physical therapists' experiences when screening for serious pathologies among their patients: a qualitative study. Phys Ther. 2022 May 5;102(5):pzac026.

10. Yusuf M, Finucane L, Selfe J. Red flags for the early detection of spinal infection in low back pain. BMC Musculoskeletal Disorders. 2019; 20(606).

11.  Verhagen AP, Downie A, Maher CG, Koes BW. Most red flags for malignancy in low back pain guidelines lack empirical support: a systematic review. Pain. 2017;158(10):1860-8.

12.  Verhagen AP, Downie A, Popal N, Maher C, Koes BW. Red flags presented in current low back pain guidelines: a review. European Spine Journal. 2016 Sep 1;25(9):2788-802.

13.  Finucane L, Selfe J, Mercer C, Greenhalgh S, Downie A, Pool A et al. An evidence informed clinical reasoning framework for clinicians in the face of serious pathology in the spine course slide.