Clinical Thresholds Index

What this index covers

Threshold index

Search thresholds across specialties.

Threshold look-up

Point-of-care threshold access.

Risk management

Audit visibility for threshold drift.

Understanding Clinical Thresholds

Clinical thresholds are specific, evidence-based values or criteria used in healthcare to guide decision-making. They represent the point at which a clinical action, such as initiating treatment, ordering a diagnostic test, or making a referral, is recommended. These thresholds are fundamental to standardising care, reducing unwarranted variation, and ensuring patient safety.

What Are Clinical Thresholds?

A clinical threshold is a predefined cut-off point derived from clinical guidelines, research evidence, and expert consensus. They can be numerical (e.g., a haemoglobin A1c level of 48 mmol/mol for diagnosing diabetes) or categorical (e.g., specific symptoms triggering a sepsis alert). Thresholds are applied across numerous domains, including:

Diagnosis: Criteria for confirming or ruling out a condition.
Treatment: Levels indicating when to start, modify, or stop a therapy.
Referral: Triggers for specialist consultation or hospital admission.
Risk Stratification: Values that categorise patients into risk groups (e.g., low, medium, high).
Safety Monitoring: Parameters for detecting adverse events or clinical deterioration.

Why Clinical Thresholds Matter

The consistent application of validated clinical thresholds is a cornerstone of clinical governance and patient safety. Their importance is multi-faceted:

Standardisation of Care: Thresholds help reduce practice variation between clinicians and organisations, promoting equity and consistency in patient management.
Evidence-Based Practice: They translate complex research findings into actionable, point-of-care decisions.
Patient Safety: Correct thresholds prevent both under-treatment (missing critical interventions) and over-treatment (exposing patients to unnecessary risks and costs).
Audit and Compliance: They provide a measurable standard against which clinical practice can be audited for quality improvement and regulatory compliance.
Efficiency: Streamlining decision-making supports clinicians and helps optimise the use of healthcare resources.

How the Clinical Thresholds Index is Used

CliniSearch's Clinical Thresholds Index is designed for practical, everyday use by healthcare professionals. It functions as a centralised, searchable repository.

Search and Discovery: Users can search for thresholds by clinical condition, specialty, or type of decision (e.g., "referral," "treatment"). Each entry is tagged for easy filtering.
Point-of-Care Access: The index is optimised for quick access during patient consultations, providing the necessary value and citation directly.
Verification and Validation: Every threshold is linked to its source, such as NICE guidelines, Royal College recommendations, or peer-reviewed literature, allowing clinicians to verify the evidence base.
Audit and Governance: Organisations can use the index as a reference point for clinical audits to monitor adherence to guidelines and identify potential "threshold drift"—where practice gradually deviates from the evidence-based standard.

Practical Checklist for Using Clinical Thresholds

Integrating thresholds safely and effectively into clinical practice requires a systematic approach. Use this checklist to guide your use of the index and application of thresholds.

Before Application

Verify the Source: Confirm that the threshold is sourced from a current, authoritative guideline (e.g., NICE, SIGN, specialist society). Check the publication or revision date.
Understand the Context: Review the specific patient population, clinical setting, and intended use for which the threshold was validated. Is it applicable to your patient?
Check for Cautions or Exclusions: Look for any footnotes or tags indicating special circumstances, contraindications, or patient groups where the threshold may not apply.

During Clinical Decision-Making

Apply Clinical Judgement: Use the threshold as a decision-support tool, not a replacement for holistic clinical assessment. Consider co-morbidities, patient preferences, and individual circumstances.
Document the Decision: Clearly note the threshold used and the resulting action in the patient record. This supports audit trails and clinical governance.
Communicate with the Patient: Where appropriate, explain how the threshold informs the recommended plan of care, supporting shared decision-making.

For Audit and Governance

Monitor Adherence: Use the index as a benchmark for clinical audit to measure how often practice aligns with recommended thresholds.
Identify and Address Drift: Investigate systematic deviations from thresholds. This may reveal training needs, system issues, or areas where local policy requires review.
Stay Updated: Subscribe to updates from CliniSearch to be notified when thresholds are revised based on new evidence or guidelines.

Sources and Evidence Base

The thresholds within this index are curated from nationally and internationally recognised sources to ensure reliability and validity. Primary sources include:

National Institute for Health and Care Excellence (NICE): Guidelines, technology appraisals, and clinical knowledge summaries.
Scottish Intercollegiate Guidelines Network (SIGN): Evidence-based clinical guidelines for Scotland.
Royal Colleges and Specialist Societies: Professional guidance from bodies such as the Royal College of Physicians (RCP), Royal College of General Practitioners (RCGP), and British Thoracic Society (BTS).
International Guidelines: Selected guidelines from organisations like the European Society of Cardiology (ESC) or American Diabetes Association (ADA) where they are widely adopted in UK practice.
Systematic Reviews and Meta-Analyses: Key studies published in high-impact, peer-reviewed journals.

Each threshold entry includes a clear citation to its source, enabling clinicians to access the full context and evidence rationale.

Common Clinical Threshold Examples

To illustrate the practical application of thresholds, here are common examples from different medical specialties that demonstrate their role in clinical decision-making.

Cardiology

Hypertension Diagnosis: Clinic blood pressure ≥140/90 mmHg (or ambulatory ≥135/85 mmHg) for diagnosis of stage 1 hypertension in adults.
Statin Initiation: Consider statin therapy for primary prevention in adults with a 10-year QRISK2 score ≥10%.
Heart Failure Referral: Refer for specialist assessment and echocardiography within 2 weeks if N-terminal pro-B-type natriuretic peptide (NT-proBNP) is >2000 pg/mL.

Diabetes

Diabetes Diagnosis: HbA1c ≥48 mmol/mol (6.5%) confirms diagnosis of diabetes mellitus.
Hypoglycaemia Action: Blood glucose <4.0 mmol/L requires carbohydrate intake and treatment review.
Retinal Screening: Annual digital retinal screening for all patients with diabetes aged 12 and over.

Infectious Diseases

Sepsis Alert (NEWS2): A NEWS2 score of 5 or more triggers an urgent clinical review for possible sepsis.
UTI Antibiotic Choice: Use nitrofurantoin as first-line for uncomplicated lower UTI in non-pregnant women, unless eGFR <45 ml/min.
HIV Testing: Offer and recommend HIV testing to all patients registering in general practice in high prevalence areas (>2/1000).

Mental Health

Depression Severity: PHQ-9 score of 10-14 indicates moderate depression, suggesting psychological interventions.
Eating Disorder Referral: Refer urgently to specialist mental health services if BMI <18.5 kg/m² with rapid weight loss or purging behaviours.
Alcohol Use Disorder: AUDIT-C score of 5 or more indicates hazardous drinking and requires brief intervention.

Implementing Thresholds in Clinical Systems

For healthcare organisations, systematically implementing clinical thresholds into electronic health records (EHRs) and clinical decision support systems (CDSS) can significantly enhance patient safety and guideline adherence.

Key Implementation Considerations

System Integration: Thresholds should be embedded within workflow tools such as order sets, alert systems, and documentation templates to prompt clinicians at the point of decision.
Local Adaptation: While national guidelines provide the foundation, thresholds may need local validation and adaptation considering population demographics and service capacity.
Alert Fatigue Management: Design CDSS alerts to be specific, actionable, and infrequent to avoid clinicians ignoring important prompts.
Stakeholder Engagement: Involve clinical leads, IT teams, and governance committees in selecting and implementing thresholds to ensure buy-in and practical utility.
Training and Education: Provide training to clinical staff on the purpose and correct interpretation of implemented thresholds.

Monitoring and Quality Improvement

Once implemented, continuous monitoring is essential to maintain the effectiveness of clinical thresholds:

Regular Audits: Conduct periodic audits to measure adherence rates and identify patterns of deviation.
Feedback Loops: Establish mechanisms for clinicians to provide feedback on threshold usability and clinical relevance.
Update Protocols: Create a formal process for reviewing and updating thresholds in response to new evidence or guideline changes.
Performance Dashboards: Use data analytics to create dashboards that show threshold adherence metrics for clinical teams and governance committees.