Medical calculators and clinical scores
Next to its cited answers, AskMed publishes medical calculators on getaskmed.com: named clinical scores and lab estimates such as eGFR, the Wells scores, CURB-65, CHA₂DS₂-VASc, HAS-BLED, Child-Pugh and MELD. Each one is built from the original paper or guideline, links to it by DOI and explains how the score works and where it falls short. The calculators run in any web browser on a phone, tablet or computer. They are web pages, not part of the iPhone or Android app.
- Web
- Not inside the apps
What the calculators are
AskMed's medical calculators are single-purpose web pages, one per clinical score or lab estimate, at getaskmed.com/tool. Each page follows the same layout: a one-line intro, the calculator itself, then sections on how it works, what the result categories mean, its limits, a short FAQ and the sources. You tick the criteria or enter the lab values, and the result updates as you go, with the category or risk group and the figure the original study reported for it, such as 30-day mortality for each CURB-65 group. The calculators cover scores and lab estimates only. None of them gives a drug dose, a dose adjustment, an infusion rate or anything that tells you how much of a drug to give, in line with the rule that runs through all of AskMed. There are 11 calculators today, listed below, covering kidney function, venous thromboembolism, electrolytes, ECG intervals, atrial fibrillation, liver disease and pneumonia.
- eGFR calculator: CKD-EPI 2021 without a race term, with the KDIGO GFR category.
- Wells score for DVT: the 2003 two-level and 1997 three-level models.
- Wells score for PE: PE likely or unlikely, and low, moderate or high probability.
- Corrected calcium: total calcium adjusted for albumin, in mg/dL or mmol/L.
- QTc calculator: Bazett, Fridericia, Framingham and Hodges at once.
- CHA₂DS₂-VASc: stroke risk in atrial fibrillation, plus the ESC CHA₂DS₂-VA.
- HAS-BLED: 1-year major bleeding risk in atrial fibrillation.
- Child-Pugh score: cirrhosis severity, class A, B or C.
- Anion gap: with optional potassium and the albumin correction.
- CURB-65: pneumonia severity with 30-day mortality from the original study.
- MELD score: MELD, MELD-Na with OPTN rules, and MELD 3.0.
How the calculators are built
Every AskMed calculator is built from the paper or guideline that defined it, and the page says which one. The formula comes from the original source, which is linked by DOI in the page's Sources section, so you can check the cut-offs and points yourself: CURB-65 from Lim and colleagues in Thorax in 2003, for example, and eGFR from the CKD-EPI 2021 equation published in the New England Journal of Medicine. Where a score has more than one version in use, the page shows them, such as MELD, MELD-Na and MELD 3.0, or the 1997 and 2003 Wells DVT models. Each calculator's math sits in its own script and is tested against a worked example from the paper or hand-checked numbers before it goes live; a calculator whose published formula can't be confirmed is not published. The calculations run in your browser only, and the values you type are not sent anywhere.
Units are handled as the sources state them, for example calcium in mg/dL or mmol/L and urea or BUN for CURB-65.
When the calculators help
The calculators help when you need a score quickly and want to see exactly where it comes from. A doctor admitting a patient with pneumonia can work out CURB-65 and see the mortality the derivation cohort showed for that score. A doctor reviewing a patient with atrial fibrillation can score CHA₂DS₂-VASc and HAS-BLED side by side, with the guideline bands for each. A nurse can check a corrected calcium against the lab's albumin, or a QTc from an ECG's QT and heart rate. A pharmacist can estimate kidney function with CKD-EPI 2021 to support a medication review, while taking any dose change from the label. A medical student can learn each score by ticking criteria and reading why the cut-offs exist, with the original paper one click away. A researcher can check which version of a score a study used. For the reasoning around a score, ask AskMed in the app, for example "What is the HAS-BLED score used for?", and get a cited answer.
Get the app on the App Store or Google Play, or use it on the web.
Limits of the calculators
The calculators have the limits of the scores they implement, and each page lists its own. A clinical score summarizes risk in a population; it does not decide care for one patient, and it should be read alongside history, examination and local guidance. Many scores were derived in specific settings, such as adults admitted to hospital, and may not apply to children, pregnancy or outpatients. Lab estimates such as eGFR and corrected calcium are approximations with known weaknesses, for example against measured GFR or ionized calcium, which the pages explain. The calculators give no drug doses or dose adjustments. They are web pages on getaskmed.com, not features inside the iPhone, iPad or Android app, and there are 11 of them, so many scores are not covered yet. The math is tested, but enter values carefully, check the units your lab reports, and open the source paper when a result will change what you do.
Frequently asked questions
Which calculators does AskMed have?
eGFR (CKD-EPI 2021), Wells for DVT, Wells for PE, corrected calcium, QTc, CHA₂DS₂-VASc, HAS-BLED, Child-Pugh, anion gap, CURB-65 and MELD.
Are the calculators in the AskMed app?
No. They are web pages on getaskmed.com and work in any browser. In the app you can ask about any score and get a cited answer.
Where do the formulas come from?
From the original paper or guideline for each score, linked by DOI in the Sources section of each page.
Is what I type sent anywhere?
No. The calculations run in your browser, and the values you enter are not sent.
Do the calculators give doses?
No. They cover scores and lab estimates only, never a dose, a dose adjustment or an infusion rate.
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