Routine Laboratory Testing Rarely Improves Emergency Department Medical Screening for Adult Psychiatric Presentations

Routine Laboratory Testing Rarely Improves Emergency Department Medical Screening for Adult Psychiatric Presentations

Highlights

Medical screening of adults presenting to the emergency department with psychiatric complaints can be organized into 8 domains: laboratory testing, history taking, vital signs, physical examination, diagnostic imaging, screening tools, electrocardiography, and system-level factors.

The strongest volume of evidence concerns laboratory testing, history, and vital signs, yet most original studies are retrospective, limiting confidence in diagnostic accuracy and causal inference.

Across society recommendations, routine laboratory testing is generally discouraged for otherwise low-risk psychiatric emergency presentations, with emphasis instead on targeted assessment and collaboration between emergency medicine and psychiatry.

No identified society recommendation fully met National Academy of Medicine standards for trustworthy guidelines or formal GRADE methodology, underscoring the need for better evidence synthesis and stronger guideline development.

Background

Adults who present to the emergency department (ED) with psychiatric symptoms often require rapid evaluation at the intersection of two clinical priorities. The first is to identify acute medical illness that may be causing, mimicking, or exacerbating psychiatric symptoms. The second is to avoid unnecessary testing that delays psychiatric care, prolongs ED boarding, increases cost, and may not improve patient outcomes. This evaluation process is frequently referred to as “medical clearance,” although many experts prefer the term “medical screening” because it better reflects what clinicians can realistically achieve in the ED: identifying immediate medical instability or alternative diagnoses rather than certifying the complete absence of disease.

The issue is clinically important because psychiatric ED presentations are common and heterogeneous. Agitation, suicidal ideation, psychosis, intoxication, delirium, severe mood symptoms, and behavioral disturbance can each arise from primary psychiatric illness, substance use, medication effects, infection, metabolic derangement, neurologic disease, or systemic illness. Emergency clinicians therefore face a practical question every day: which components of medical screening meaningfully improve diagnostic safety, and which represent low-value routine practice?

The scoping review by Ünlü and colleagues addresses this long-standing question by mapping the literature on medical screening of adult psychiatric ED patients and appraising both original research and professional recommendations. The review is timely because variability in screening practices remains substantial across hospitals, and disagreements between ED clinicians and receiving psychiatric services continue to drive delays in care.

Study Design and Methods

This was a scoping review of the literature on medical screening of adult patients, defined as age 18 years and older, presenting to general EDs with psychiatric complaints. The authors searched Medline, PsycInfo, EMBASE, and Web of Science from database inception through April 2025. Citation searching and expert consultation supplemented the electronic search strategy.

Eligible articles included studies of any design that reported on medical screening practices in this population. The investigators charted study characteristics across all eligible publications. They also performed thematic analysis of original research articles and society statements.

The final dataset included 145 publications: 62 original research articles, 74 nonoriginal publications, and 9 society recommendations. Across the original research studies, the evidence base encompassed 34,836 patients and 1,149 health care professionals. Retrospective designs predominated, accounting for 59.7% of original research articles.

Rather than producing a pooled effect estimate, which would have been difficult given the heterogeneity of methods and outcomes, the review mapped the evidence into clinically meaningful domains. This approach is appropriate for a field characterized by variable definitions of psychiatric presentation, inconsistent use of reference standards, and diverse screening protocols.

Key Findings

1. Eight major themes define the medical screening literature

The review identified 8 recurring themes in the original literature: laboratory testing in 38 studies (62.9%), history taking in 22 studies (35.5%), vital signs in 21 studies (33.9%), physical examination in 19 studies (30.6%), diagnostic imaging in 13 studies (21.0%), medical screening tools in 10 studies (16.1%), electrocardiography in 9 studies (14.5%), and system-level factors in 8 studies (12.9%).

This framework is itself an important contribution. It shows that the field has focused most heavily on whether routine laboratory studies should be performed, while comparatively less attention has been paid to the diagnostic performance of history, bedside examination, and workflow design. Yet these latter elements are often the determinants of whether a patient truly requires further medical workup.

2. Laboratory testing remains the most studied and most contested domain

Laboratory testing accounted for nearly two-thirds of the original research literature, confirming that it remains the central fault line in “medical clearance” debates. Although the abstract does not provide pooled estimates of abnormal test yield, the review’s overall conclusion aligns with many prior policy statements: indiscriminate routine laboratory testing in psychiatric ED patients is often of low value, particularly in younger, alert, hemodynamically stable patients with a known psychiatric history and no concerning findings on history or examination.

The practical implication is not that laboratory tests are unimportant, but that their usefulness depends on pretest probability. Targeted testing may be essential in patients with first-episode psychosis, older age, abnormal vital signs, altered cognition, substance use concerns, medication toxicity, signs of infection, endocrine symptoms, or suspected metabolic or neurologic disease. What the review suggests is that a blanket requirement for labs before psychiatric evaluation is difficult to justify on current evidence.

3. History, vital signs, and physical examination remain foundational

History taking, vital signs, and physical examination were the next most commonly studied themes. Together, they represent the core clinical assessment that should precede any decision about further testing. These bedside elements are particularly important because many dangerous medical causes of psychiatric symptoms can be suspected early through a focused interview and examination: delirium, intoxication or withdrawal, head injury, sepsis, hypoglycemia, hypoxia, thyroid disease, medication adverse effects, and central nervous system pathology among them.

The review emphasizes that the literature supports structured clinical assessment over reflex testing. In practice, abnormalities in level of consciousness, orientation, speech, gait, pupillary findings, temperature, blood pressure, pulse, respiratory rate, oxygen saturation, or glucose measurement may be more informative than routine chemistry panels ordered without a specific clinical question.

4. Evidence for imaging, ECG, and screening tools is smaller and more selective

Diagnostic imaging, electrocardiography, and formal screening tools were each represented in a minority of studies. This likely reflects appropriate selective use. Imaging may be warranted when trauma, focal neurologic deficits, new cognitive change, severe headache, seizure, or other red flags are present. ECG is especially relevant in overdose, stimulant toxicity, electrolyte disturbance, syncope, chest symptoms, and before treatment with certain psychotropics in higher-risk patients. Screening tools may help standardize assessment, but the review suggests that they have not yet been validated strongly enough to replace clinician judgment.

One important takeaway is that the field still lacks robust prospective evidence defining how well these modalities discriminate low-risk from high-risk psychiatric ED patients. This creates uncertainty at the bedside and encourages defensive or institution-driven testing patterns.

5. System-level factors are underappreciated but clinically important

The 8th theme, system-level factors, deserves more attention than the literature has so far given it. Differences in local psychiatric facility requirements, transfer protocols, staffing models, access to point-of-care testing, and the relationship between ED and psychiatry services strongly influence what “medical screening” looks like in practice. In many settings, laboratory testing persists not because of compelling patient-level evidence but because receiving facilities require certain tests prior to acceptance.

This matters because system rules can create care delays without clear benefit. They may also shift clinical focus away from individualized assessment toward checklist compliance. The review’s finding that society recommendations call for collaboration between emergency medicine and psychiatry is therefore highly relevant. Improving the handoff environment may be as important as improving the test menu.

6. The evidence base is broad but methodologically limited

The principal methodological message of the review is that there is a lot of literature, but not enough high-quality literature. Most original studies were retrospective. Such designs are useful for describing practice patterns and test yields, but they are weaker for determining diagnostic accuracy, assessing missed illness rates, or establishing whether one screening strategy is safer than another.

Important unanswered questions remain: Which combination of historical and examination findings safely identifies patients who need no routine labs? What is the false-negative rate of minimalist screening strategies? How often do “medically cleared” patients later prove to have acute medical illness? Are outcomes different for first-episode psychosis compared with recurrent psychiatric presentations? Which findings should trigger broader workup in older adults or medically complex patients?

Clinical Interpretation

For frontline clinicians, the review supports a targeted, risk-based approach. Adults presenting with psychiatric complaints should still receive a real medical assessment, but not necessarily a standardized battery of tests. The most defensible strategy is to begin with history, medication review, substance use assessment, vital signs, glucose when indicated, mental status examination, and focused physical and neurologic examination. Additional tests should be ordered when prompted by age, comorbidity, abnormal findings, intoxication, withdrawal risk, ingestion history, inability to provide history, or concern for delirium or systemic illness.

This approach is also consistent with value-based care. Routine testing of low-risk patients may produce incidental abnormalities that do not explain the presentation yet trigger further workup, prolong ED length of stay, and delay psychiatric treatment. At the same time, clinicians must avoid the opposite error: assuming symptoms are purely psychiatric when medical disease is present. The review does not endorse minimalism for all patients; it argues for better discrimination.

Several higher-risk groups deserve special mention. First-episode psychosis should generally prompt broader medical consideration than recurrent psychosis in a patient with a known illness pattern. Older adults, patients with cognitive change, those with no prior psychiatric history, and those with significant substance exposure or medication changes require lower thresholds for testing. Similarly, abnormal vital signs should never be dismissed as behavioral noise without explanation.

Expert Commentary and Guideline Context

The review’s appraisal of society recommendations is especially useful. Most guidelines or position statements discouraged routine laboratory testing for all psychiatric ED presentations and instead advocated clinically guided testing. That broad consistency across professional statements suggests convergence of expert opinion despite imperfect evidence.

However, the authors also identified an important weakness: none of the society recommendations perfectly adhered to National Academy of Medicine standards for trustworthy guidelines or to GRADE methodology. This does not make the recommendations invalid, but it does mean they are less transparent and less rigorously evidence-linked than modern guideline users might expect. For a topic that affects large patient volumes, interdepartmental workflow, and healthcare spending, that gap is notable.

The review therefore sits in an interesting place between policy and evidence. Practice is moving toward targeted testing, but the supporting science remains less definitive than many assume. This should temper both rigid mandates for universal testing and overly confident claims that no testing is needed in broad patient groups.

Limitations of the Evidence Base

Several limitations should guide interpretation. First, the review is a scoping review, so its purpose is to map the literature rather than generate pooled quantitative estimates of effect or accuracy. Second, the included studies were heterogeneous in patient selection, psychiatric complaint definitions, screening protocols, and outcomes measured. Third, retrospective study predominance limits causal inference and is vulnerable to documentation bias and incomplete ascertainment of missed diagnoses. Fourth, publication and reporting biases may affect which screening strategies appear useful or low yield. Finally, society recommendations may reflect local operational realities as much as pure evidence.

These limitations do not weaken the central message that routine testing should be questioned. Rather, they explain why the field still lacks a universally accepted, highly precise medical screening algorithm.

Implications for Practice and Research

For clinical practice, this review supports replacing the vague concept of “medical clearance” with a structured, documented medical screening assessment tailored to risk. Emergency departments and psychiatric services should jointly define which findings warrant testing and which do not. Shared protocols can reduce friction, shorten ED stays, and preserve diagnostic safety.

For research, the next priority is prospective diagnostic accuracy work. Future studies should enroll consecutive psychiatric ED patients, use standardized index assessments, define reference standards clearly, and track short-term missed medical illness outcomes. Research should also focus on subgroups that likely differ in risk, including older adults, first-episode psychosis, intoxicated patients, and those with communication barriers. Pragmatic implementation studies would also help determine whether reducing routine testing improves throughput without increasing adverse events.

A second research priority is guideline quality. Professional societies should update recommendations using transparent methodology, explicit evidence grading, multidisciplinary panels, and patient-centered outcomes such as missed illness, ED length of stay, psychiatric boarding duration, and cost.

Conclusion

This scoping review provides the clearest map to date of how medical screening for adult psychiatric ED presentations has been studied. The literature clusters around 8 domains, with the greatest emphasis on laboratory testing, history taking, and vital signs. The broad direction of the evidence and of society recommendations is that routine laboratory testing should not be automatic for every psychiatric presentation. Instead, clinicians should prioritize targeted assessment guided by history, examination, vital signs, and clinical context.

At the same time, confidence in any single screening strategy remains limited because most studies are retrospective and guideline development has not consistently met modern methodological standards. The field is ready for prospective, high-quality research that can define which patients benefit from additional testing, which do not, and how emergency medicine and psychiatry can work from the same evidence base. Until then, the most defensible approach remains careful bedside evaluation, selective testing, and close interdisciplinary collaboration.

Funding and Trial Registration

Funding information was not provided in the abstract. No ClinicalTrials.gov registration number was reported in the abstract for this scoping review.

References

Ünlü L, Griese JA, Minotti B, Carpenter CR, Appenzeller-Herzog C, Sterzer P, Christ M, Azad N, Nordstrom K, Skinner C, Alsma J, Stiebel V, Kurzhals S, Abdalla Maia IW, Bingisser R, Wilson MP, Nickel CH. Medical Screening of Adult Psychiatric Patients Presenting to the Emergency Department. Annals of Emergency Medicine. 2026-06-02. PMID: 42233919.

Zun LS. Evidence-based evaluation of psychiatric patients. Journal of Emergency Medicine. 2005;28(1):35-39.

Lukens TW, Wolf SJ, Edlow JA, Shahabuddin S, Allen MH, Currier GW, Jagoda AS, American College of Emergency Physicians Clinical Policies Subcommittee. Clinical policy: critical issues in the diagnosis and management of the adult psychiatric patient in the emergency department. Annals of Emergency Medicine. 2006;47(1):79-99.

National Academy of Medicine. Clinical Practice Guidelines We Can Trust. Washington, DC: National Academies Press; 2011.

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