Bedside clinical calculators

ScoreRx

Select a validated bedside score, enter the available clinical findings, and review the result with its interpretation and source guidance. Designed for fast verification at the point of care.

10 bedside calculators Source-linked guidance Verification support

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Serum Anion Gap

AG = Na⁺ − (Cl⁻ + HCO₃⁻). The "normal" range is analyzer-dependent — older flame-photometry/colorimetric methods reported ~8–16 mEq/L, but modern ion-selective-electrode (ISE) analyzers, now standard in most US labs, typically read lower (~3–11 mEq/L). Use your own lab's stated reference range where available; this tool reports the number and both commonly-cited ranges rather than asserting a single universal cutoff.

Sodium (mEq/L)

Chloride (mEq/L)

Bicarbonate (mEq/L)

Albumin, g/dL (optional — for albumin-corrected AG)

Enter Na, Cl, and HCO₃ and click Calculate.

Fractional Excretion of Sodium (FENa)

FENa (%) = (Urine Na × Serum Cr) / (Serum Na × Urine Cr) × 100. Derived by Espinel (1976) in oliguric patients to help distinguish pre-renal azotemia from acute tubular necrosis (ATN).

Urine Sodium (mEq/L)

Serum Sodium (mEq/L)

Urine Creatinine (mg/dL)

Serum Creatinine (mg/dL)

Patient has received a loop or thiazide diuretic within the last ~24hDiuretics increase urinary Na loss independent of renal perfusion status and can push a true pre-renal FENa above 1% — this makes FENa unreliable in that setting (Carvounis et al.); the fractional excretion of urea (FEUrea, <35% pre-renal / >50% ATN) is less affected by diuretics and is generally preferred when one has been given.

Enter all four values and click Calculate.

CURB-65 — Pneumonia Severity

Lim WS et al., Thorax 2003 — derived and validated in >1000 hospitalized community-acquired pneumonia (CAP) patients across three prospective cohorts (UK, New Zealand, Netherlands). One point each; 30-day mortality rises with score. A screening/disposition aid, not a replacement for clinical judgment (e.g. hypoxemia, unstable comorbidities, and social factors are not captured by the score itself).

Confusion, new onsetOriginal criterion: Abbreviated Mental Test Score (AMTS) ≤ 8/10 — commonly assessed in US practice as new disorientation to person/place/time, or a fall in GCS, relative to baseline.

Urea > 7 mmol/L (BUN > 19 mg/dL)

Respiratory rate ≥ 30 breaths/min

Blood pressure: systolic < 90 mmHg, or diastolic ≤ 60 mmHg

Age ≥ 65 years

Assess all five criteria and click Calculate.

PERC Rule — PE Rule-Out Criteria

Kline JA et al., J Thromb Haemost 2004 (derivation), validated 2008 (n=8138). Intended only for patients the clinician has already judged to be low pre-test probability for PE — PERC's derivation/validation population was defined by unstructured clinical gestalt of <15% pretest probability, not by the Wells score. Wells ≤ 4/low-risk category is a commonly used proxy for that same population and is offered here for convenience, but it is a different instrument derived separately — the two usually, not always, agree. If all 8 criteria are negative in a genuinely low pre-test-probability patient, PE can reasonably be excluded without D-dimer.

Age ≥ 50 years

Heart rate ≥ 100 bpm

SpO₂ < 95% on room air

Hemoptysis

Exogenous estrogen use (OCPs, HRT, estrogen therapy)

Prior DVT or PE

Unilateral leg swelling

Surgery or trauma requiring hospitalization within the last 4 weeks

I have independently assessed this patient as LOW pre-test probability for PE (clinical gestalt <15%, or Wells ≤ 4/low-risk category as a proxy) — required before applying PERC

Assess all 8 criteria and click Calculate.

Glasgow Coma Scale

Teasdale & Jennett, Lancet 1974 (original Eye/Motor scale extended to the current 3-point-minimum, 15-point-maximum Eye+Verbal+Motor form by 1977). Total = Eye + Verbal + Motor, range 3–15. A GCS ≤ 8 is the widely-used threshold prompting consideration of airway protection.

Eye Opening (E)

Verbal Response (V)

Motor Response (M)

Select Eye, Verbal, and Motor responses and click Calculate.

Wells' Criteria — Deep Vein Thrombosis

Wells PS et al., N Engl J Med 2003 (dichotomized "likely/unlikely" revision of the original 1997 model). One point each unless noted; total range −2 to 9. Pre-test probability only — pairs with D-dimer and/or compression ultrasound per your institutional pathway, not a stand-alone diagnosis.

Active cancer (treatment ongoing, within 6 months, or palliative)

Paralysis, paresis, or recent plaster immobilization of the lower extremity

Recently bedridden ≥ 3 days, or major surgery within 12 weeks requiring general/regional anesthesia

Localized tenderness along the distribution of the deep venous system

Entire leg swollen

Calf swelling ≥ 3 cm larger than the asymptomatic leg (measured 10 cm below tibial tuberosity)

Pitting edema confined to the symptomatic leg

Collateral superficial (non-varicose) veins

Previously documented DVT

Alternative diagnosis at least as likely as DVT (−2 points)

Assess all criteria and click Calculate.

Wells' Criteria — Pulmonary Embolism

Wells PS et al. (original weighted score); two-tier "PE likely/unlikely" dichotomization per the Christopher Study (van Belle A et al., JAMA 2006). Pre-test probability only — this is the "Wells ≤ 4/low-risk category" referenced by the PERC rule tab.

Clinical signs/symptoms of DVT (leg swelling, pain with palpation of deep veins) (3 pts)

PE is the #1 diagnosis, or equally likely (3 pts)

Heart rate > 100 bpm (1.5 pts)

Immobilization ≥ 3 days, or surgery in the previous 4 weeks (1.5 pts)

Previous, objectively diagnosed PE or DVT (1.5 pts)

Hemoptysis (1 pt)

Malignancy (treatment within 6 months, or palliative) (1 pt)

Assess all criteria and click Calculate.

HEART Score — Chest Pain / MACE Risk

Six AJ et al., Neth Heart J 2008 (derivation); Backus BE et al., Int J Cardiol 2013 (prospective multicenter validation, n=2440). Estimates 6-week risk of major adverse cardiac events (MACE) in ED chest-pain patients with a non-diagnostic initial workup — not for use with a confirmed STEMI or an already-diagnostic ECG/troponin.

History

ECG

Age (years)

Risk Factors (HTN, hyperlipidemia, DM, obesity BMI>30, current/recent-quit smoking, family history of CAD, or known atherosclerotic disease)

Troponin (× local upper limit of normal)

Select History, ECG, Risk Factors, Troponin, and enter Age, then click Calculate.

Glasgow-Blatchford Score — Upper GI Bleed

Blatchford O et al., Lancet 2000. Predicts need for transfusion, endoscopic/surgical/radiologic intervention, or death in suspected upper GI bleeding — calculated entirely from history/labs/vitals, without endoscopy. Score range 0–23.

BUN (mg/dL)

Hemoglobin (g/dL)

Sex

Systolic BP (mmHg)

Pulse (bpm)

Melena at presentation (1 pt)

Syncope (2 pts)

Known hepatic disease (history of, or exam/labs suggesting, chronic liver disease) (2 pts)

Known cardiac failure (2 pts)

Enter BUN, Hgb, sex, SBP, pulse, and assess the four checkboxes, then click Calculate.

NIH Stroke Scale (NIHSS)

15-item standardized neurological exam, 0–42 points, higher = more severe deficit. Score each item as examined; do not skip items or infer a score not directly observed. This is a score-entry/summing tool, not a substitute for a certified NIHSS examination: it sums the item scores you enter and checks the two default-scoring rules below, but it does not itself administer the exam, provide the standardized stimuli (pictures/naming/sentence cards), or enforce every official administration rule (e.g. substituting a one-step command when the hands can't be used, or accommodating a written response to test language in an intubated patient) — those depend on the examiner correctly applying the official NINDS instructions at the bedside. It does not itself determine reperfusion-therapy eligibility.

1a. Level of Consciousness

1b. LOC Questions (month, age)

1c. LOC Commands (open/close eyes, grip/release hand)

2. Best Gaze

3. Visual Fields

4. Facial Palsy

5a. Motor Arm — Left

5b. Motor Arm — Right

6a. Motor Leg — Left

6b. Motor Leg — Right

7. Limb Ataxia (score only if out of proportion to weakness; scores 0 if paralysis or noncomprehension prevents testing)

8. Sensory

9. Best Language

10. Dysarthria

11. Extinction and Inattention (Neglect)

Score all 15 items and click Calculate.

References

Feldman M, Soni N, Dickson B. Influence of hypoalbuminemia or hyperalbuminemia on the serum anion gap. J Lab Clin Med. 2005;146(6):317-320. PMID 16310513. (Source of the albumin-corrected anion gap formula used above: adjusted AG = AG + 2.3 × (4.0 − albumin), from a regression in 5328 patients. Abstract read directly; full text not accessed. Note: a commonly-cited alternative coefficient of 2.5, from Figge et al., is a different, separate estimate — this tool uses Feldman's 2.3 rather than conflating the two.)
Kraut JA, Nagami GT. The serum anion gap in the evaluation of acid-base disorders: what are its limitations and can its effectiveness be improved? Clin J Am Soc Nephrol. 2013;8(11):2018-2024. Open access (PMC3817903). (Corroborates the ISE-era reference-range shift for anion gap — lower than the classic 8–16 mEq/L figure derived from older flame-photometry/colorimetric assays — used for the analyzer-dependence caveat above.)
Espinel CH. The FENa test. Use in the differential diagnosis of acute renal failure. JAMA. 1976;236(6):579-581. (Original FENa derivation, oliguric patients only; <1% pre-renal, >2% ATN in that population. Paywalled; not read directly — cutoffs cross-checked against multiple independent secondary sources that converge on the same figures.)
Carvounis CP, Nisar S, Guro-Razuman S. Significance of the fractional excretion of urea in the differential diagnosis of acute renal failure. Kidney Int. 2002;62(6):2223-2229. PMID 12427149. (Source of the FEUrea <35% pre-renal / >50% ATN cutoffs and the diuretic-insensitivity rationale referenced in the FENa diuretic caveat above. Abstract read directly; full text not accessed.)
Lim WS, van der Eerden MM, Laing R, et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax. 2003;58(5):377-382. Open access (PMC1746657). (Original CURB-65 derivation/validation and mortality-band data used above.)
Kline JA, Mitchell AM, Kabrhel C, Richman PB, Courtney DM. Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism. J Thromb Haemost. 2004;2(8):1247-1255. PMID 15304025. (Original PERC rule derivation.)
Kline JA, Courtney DM, Kabrhel C, et al. Prospective multicenter evaluation of the pulmonary embolism rule-out criteria. J Thromb Haemost. 2008;6(5):772-780. PMID 18318689. (PERC prospective validation, n=8138, confirming the 8-criteria/low-pretest-probability-only use case reflected above. Both PERC papers paywalled; not read directly — the 8 criteria and their exact thresholds were cross-checked across multiple independent, freely-accessible secondary sources that converge exactly.)
Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet. 1974;2(7872):81-84. (Original GCS; the current 3-point-minimum/15-point-maximum Eye+Verbal+Motor form reflects the 1977 refinement distinguishing abnormal flexion from normal flexion in the motor score, per subsequent historical review — see next reference. Original paper paywalled; not read directly.)
Reith FCM, Van den Brande R, Synnot A, Gruen R, Maas AIR. The reliability of the Glasgow Coma Scale: a systematic review. Intensive Care Med. 2016;42(1):3-15. Open access (PMC4698379). (Corroborates the current 3–15 scoring convention and the "T" (untestable/intubated verbal) annotation convention used above.)
Wells PS, Anderson DR, Rodger M, et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med. 2003;349(13):1227-1235. (Source of the 2003 "likely/unlikely" dichotomized Wells DVT criteria, weights, and the ≥2 likely / ≤1 unlikely cutoff used above. Paywalled; not read directly — the 10 criteria, their point values, and the cutoff were cross-checked against 3 independent, freely-accessible secondary sources that converge exactly, including one that itself cites this paper directly.)
Wells PS, Anderson DR, Rodger M, et al. Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer. Ann Intern Med. 2001;135(2):98-107. (Original weighted 7-criterion Wells PE score and 3-tier low/moderate/high stratification. Paywalled; not read directly — cross-checked against 2 independent secondary sources that converge exactly on all 7 criteria and point values, including the half-point weightings.)
van Belle A, Büller HR, Huisman MV, et al; Christopher Study Investigators. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA. 2006;295(2):172-179. (Source of the two-tier "PE likely" (>4) / "PE unlikely" (≤4) dichotomization of the Wells PE score used above, matching the "Wells ≤4/low-risk category" language already used in the PERC tab. Paywalled; not read directly — the ≤4/>4 cutoff was corroborated against 2 independent secondary sources.)
Six AJ, Backus BE, Kelder JC. Chest pain in the emergency room: value of the HEART score. Neth Heart J. 2008;16(6):191-196. (Original HEART score derivation: the 5-component History/ECG/Age/Risk factors/Troponin structure, 0-2 points each, and the low ≤3 / moderate 4-6 / high ≥7 risk bands. Abstract-level details read via an open-access PMC review citing this paper directly; original full text not independently accessed — the exact point boundaries (age <45/45-65/≥65; troponin ≤1×/1-3×/>3× normal) were corroborated against 2 independent secondary sources that converge exactly.)
Backus BE, Six AJ, Kelder JC, et al. A prospective validation of the HEART score for chest pain patients at the emergency department. Int J Cardiol. 2013;168(3):2153-2158. (Prospective multicenter validation, n=2440, of the HEART score and its MACE risk bands referenced above.)
Blatchford O, Murray WR, Blatchford M. A risk score to predict need for treatment for upper-gastrointestinal haemorrhage. Lancet. 2000;356(9238):1318-1321. PMID 11073021. (Original Glasgow-Blatchford Score derivation: all 8 criteria, their point values, and the 0-23 score range used above. Paywalled; not read directly — cross-checked against 3 independent secondary sources, including one open-access PMC paper whose own table cites this reference directly, all of which converge exactly on every point value.)
National Institute of Neurological Disorders and Stroke (NINDS). NIH Stroke Scale (current official version/instructions). ninds.nih.gov. (Primary source of the 15-item point values used above. The official NINDS PDF returned an access-blocked response in this environment and was not read directly — every item's exact wording and point values were corroborated against 5+ independent, freely-accessible hospital/stroke-center training references that converge exactly, including the total-score arithmetic (42) reconstructed independently from the 15 per-item maxima. Confirmed separately via search: the official form also permits "UN" for items 5a/5b, 6a/6b, and 7 on amputation/joint fusion, now reflected above alongside item 10's — this tool reproduces the point values and untestable-item conventions, not every administration/default-scoring rule; see the card's own disclaimer for which rules that leaves to the examiner.)
Brott T, Adams HP Jr, Olinger CP, et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke. 1989;20(7):864-870. (Original derivation of the scale.)
Lyden P, Brott T, Tilley B, et al, for the NINDS TPA Stroke Study Group. Improved reliability of the NIH Stroke Scale using video training. Stroke. 1994;25(11):2220-2226. (Source of the standardized examiner-training conventions — including the untestable/"UN" item convention reflected in the Dysarthria item above — still in use today.)

Sourcing note: several of the above (Espinel 1976, both Kline PERC papers, Teasdale & Jennett 1974, both Wells papers, the Christopher Study, Six 2008, Blatchford 2000, and the official NINDS NIHSS instructions) are papers/documents that returned paywall/access errors in this environment (or, for Six 2008, were only accessible at abstract/secondary-citation depth) and were not read in full text directly. In each case the specific numeric criteria used in this tool were corroborated against 2 or more independent, freely-accessible secondary sources rather than presented as directly verified against the original — see the individual reference notes above for which sources were and weren't read directly.

Clinical Disclaimer: ScoreRx is a reference and verification aid for licensed healthcare professionals. It is not autonomous clinical software and does not replace clinical judgment, patient-specific assessment, or institutional protocol.