Signs & Symptoms of Infections: When to Notify a Clinician

If you care for older adults at home or in long-term care, spotting early changes is everything. This document summarizes the INTERACT 4.0 guidance alongside widely used criteria (McGeer surveillance definitions, AHRQ “Minimum Criteria,” and Loeb minimum criteria) to help teams recognize concerning patterns, decide when to notify a clinician, and avoid unnecessary antibiotics. It’s a practical, bedside-friendly overview—not a diagnostic rulebook—so you can escalate concerns consistently and support safer care.

What this file is (and isn’t)

Purpose: Give clinically sound, consistent thresholds for clinician notification (MD/NP/PA) when a resident’s condition changes. It is not designed to diagnose specific infections or to mandate antibiotic therapy.
Why that matters: Published diagnostic criteria differ across sources; this guide harmonizes notification triggers so facilities don’t juggle multiple sets at once and can implement reliably. Facilities should choose one approach and use it consistently, then follow antibiotic stewardship principles when antibiotics are considered. Vs and symptoms of infections

Vital signs & red flags (quick reference)

These are common notify-now cutoffs or prompts drawn from INTERACT and aligned sources:

Temperature
- INTERACT fever: >100.5°F (38.1°C)
- McGeer examples: single oral >100°F (37.8°C); repeated oral >99°F (37.2°C) or rectal >99.5°F (37.5°C); or >2°F (1.1°C) over baseline.
Pulse (apical/heart rate): >100 or <50 beats/min (INTERACT).
Respiratory rate: >28/min or <10/min (INTERACT). Many respiratory criteria flag ≥25/min as concerning (McGeer/AHRQ).
Blood pressure: Systolic <90 or >200 mmHg (INTERACT).
Oxygen saturation: <90% (INTERACT). Respiratory infection criteria often flag <94% on room air or a drop >3% from baseline (McGeer/AHRQ). Vs and symptoms of infections

Lower respiratory infection (LRI): patterns that matter

Common symptoms: new/worsening cough, ↑sputum, pleuritic chest pain, new dyspnea, new lung exam findings (rales/wheeze).
Escalate when fever, RR ≥25, O₂ <94% or >3% drop, delirium, rigors, tachycardia, or chest-x-ray suggests pneumonia.
Key point: Loeb criteria help decide when antibiotics are justified; INTERACT focuses on when to call so a clinician can assess. Vs and symptoms of infections

Urinary tract infection (UTI): with and without a catheter

Without catheter (watch for): dysuria; suprapubic pain; hematuria; new/worsening urgency, frequency, or incontinence. Fever with these localizing signs increases concern.
With catheter (watch for): fever/rigors/new hypotension without another source; new suprapubic or costovertebral angle tenderness; purulent discharge; or acute change in mental or functional status with leukocytosis.
Do not start antibiotics for asymptomatic bacteriuria, and remember foul-smelling or cloudy urine alone is not an indication to treat. Vs and symptoms of infections

Gastrointestinal symptoms & specific infections

Notify for: new/worsening nausea/vomiting, diarrhea (≥3 loose/liquid stools in 24 h), constipation (no BM in 3 days), abdominal pain/distension, blood in stool/vomit, jaundice, or outbreak-like clusters.
Norovirus: diarrhea and/or vomiting plus lab confirmation (PCR/EIA/EM) or outbreak features (e.g., many with vomiting, 24–48 h incubation, 12–60 h illness).
Clostridioides difficile: diarrhea or toxic megacolon plus lab toxin/organism evidence or endoscopic/histologic pseudomembranes.
The file also clarifies “primary” vs “recurrent” C. diff episodes (≥8 weeks apart vs ≤8 weeks after prior onset). Vs and symptoms of infections

How to use this guide in your setting

Adopt one consistent standard for when to notify clinicians about suspected infections (e.g., INTERACT thresholds) so teams act uniformly across shifts.
Pair with diagnostic/therapy criteria (McGeer, AHRQ, Loeb) when clinicians evaluate whether antibiotics are appropriate.
Reinforce stewardship: Only start antibiotics when minimum criteria are met; document rationale; re-evaluate at 48–72 hours.
Teach the “why”: Explain to staff and families that not every fever or cloudy urine is an infection; watch for clusters and trends (e.g., rising RR, dropping O₂).
Escalate early changes: New cough + RR ≥25, acute delirium with vital-sign shifts, or sudden O₂ decline should trigger timely clinician contact. Vs and symptoms of infections

Key takeaways

Notification ≠ diagnosis. INTERACT criteria streamline when to call; treatment decisions still rely on clinical judgment and diagnostic criteria.
Vital signs tell a story. RR, O₂ sat, and modest fevers over baseline are often earlier, more sensitive changes than a single high temperature.
UTI pitfalls: Avoid treating asymptomatic bacteriuria and remember smell/cloudiness alone is not enough.
Outbreak awareness: GI clusters, especially with vomiting and short incubation, may signal norovirus and warrant rapid infection-control steps. Vs and symptoms of infections

Disclaimer

This blog is for education only and is not medical advice. Criteria and thresholds are summarized from the source document and related references for clinician notification and surveillance guidance; they do not replace a clinician’s assessment, facility policy, or local/state/federal regulations. If you suspect a medical emergency, call 911. Vs and symptoms of infections

Source

“INTERACT Guidance on Identification and Management of Infections” (INTERACT 4.0 tables comparing INTERACT, McGeer, AHRQ, and Loeb criteria; includes stewardship references).

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Signs & Symptoms of Infections: When to Notify a Clinician (INTERACT, McGeer, AHRQ, Loeb)