Calc Function

  • Diagnosis
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  • Prognosis
  • Formula
  • Treatment
  • Algorithm
  • Disease
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    Frequently Asked Questions

    About MDCalc

    • What is MDCalc?
    • Who is MDCalc?
    • Who should use MDCalc?
    • Is MDCalc useful to non-physician medical professionals? To whom?
    • I’m a patient. Can I use MDCalc?
    • You have ads on the site. Do advertisers influence content?
    • How many medical professionals use MDCalc?
    • How do I earn CME through MDCalc?
    • Is MDCalc CME accredited?
    • Who are MDCalc’s partners?

    About Calculators and Contributors

    • Where do these scores come from? Who are the “creators”?
    • What does it mean that a calculator has been “Contributed By” and “Reviewed By” someone?
    • Can you add [this score]? How do you decide what gets added to MDCalc?
    • How do we know if contributors are biased or have conflicts of interest?
    • How many calculators exist?

    Using MDCalc

    • How do I know if there’s a calculator that’s applicable for my patient / clinical scenario?
    • If there are two calculators for the same purpose, how do I decide which one to use?
    • When do calculators work best? Not as well?
    • What’s the best way to explain a calculator’s results to a patient?
    • How do units work?
    • Where does “Copy Results” copy to?
    • What browsers are supported?
    • Do you have an app? How is the website different from the apps?

    Beyond Calculators

    • What else does MDCalc offer, beyond calculators?
    • What are Guidelines?
    • What are Decision Aids?
    • What is the EHR integration?

    About MDCalc

    What is MDCalc?

    MDCalc is a site for medical professionals, to help us do calculations, process algorithms and scores, and assess risk—all using the latest and best evidence—to make patients better, faster.

    Who is MDCalc?

    MDCalc is a 14-year-old medical reference that was founded (and is still owned and run) by two practicing academic emergency physicians, Dr. Graham Walker and Dr. Joseph Habboushe. There is no outside money or influence in MDCalc, beyond the hundreds of top academics who have created, studied, and written about medical calculators and clinical decision rules for MDCalc.

    Who should use MDCalc?

    MDCalc is meant to be used by medical professionals only.

    Today nearly every specialty of medicine uses medical calculators and clinical decision tools, as they have grown in popularity as a smart and powerful way to apply evidence based medicine to improve the care of patients. If you’d like to see what calcs exist for your specialty, set your specialty in Preferences, or use our discovery feature based on Chief Complaint or Disease + Calc Function, for example. You can find out more about how and when to use each calc by reading the tabs on each page, written by expert academic contributors.

    Is MDCalc useful to non-physician medical professionals? To whom?

    Yes, many types of medical professionals who make clinical decisions find MDCalc useful–not only physicians, physician assistants, nurse practitioners, and medical students, but also nurses, EMTs, allied health, and more. However, MDCalc is only meant for the use of medical professionals, and should not be used by patients or healthcare consumers.

    I’m a patient. Can I use MDCalc?

    MDCalc is meant for use by medical professionals only.

    You have ads on the site. Do advertisers influence content?

    We have a strict separation of advertising and content: What looks like an ad is an ad; what doesn’t look like an ad is not influenced by advertisers.

    Ads are clearly marked as such, and MDCalc’s content is developed by and only by MDCalc’s editorial team and our contributing authors, who are practicing academic doctors who have met our conflicts policy (you can see more and apply at mdcalc.com/contributors).

    How many medical professionals use MDCalc?

    As our users do not need to register, our numbers are only approximate, but through our best methods (and third-party surveys of physicians), as of the beginning of 2018 approximately 65% of U.S. physicians used MDCalc on a regular (weekly) basis, and millions of physicians worldwide. Our internal numbers have shown we have grown significantly since this estimate. This may make MDCalc the most broadly used physician medical reference! We would have never imagined this would be the case when we started MDCalc.

    How do I earn CME through MDCalc?

    MDCalc calculators have useful point-of-care content written by unbiased expert contributors in the tabs "When to Use," "Next Steps," etc. This content is CME-eligible, and providers are now able to earn CME credits and fulfill their annual requirements by reviewing this content for 100+ calcs.

    MDCalc CME is currently available for Nurse Practitioners, Physician Assistants, and Physician Attendings in the US only. To earn CMEs, you need to sign up for an MDCalc account. Click on ALL FIVE tabs of content in a calc (three tabs above the content, two below) or click Earn CME on the calc page to earn ½ hour of CME per calc. You can go to the CME Dashboard from the hamburger menu to answer the standard questions and redeem your CME certificates.

    Not all calcs offer CMEs—just those with significant MDCalc contributor content. As we’re a free service, we have several options on how providers can get CMEs on MDCalc: by paying for a subscription with their (often reimbursable) CME budget; by working for a hospital system who’s bought a group plan (with our EHR integration packages); or by getting credit rewards for contributing to MDCalc, bringing in new users, etc.

    For more FAQs about CME, click here.

    Is MDCalc CME accredited?

    Yes, in support of improving patient care, our CME has been planned and implemented by the Postgraduate Institute for Medicine and MD Aware LLC. Postgraduate Institute for Medicine is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.

    Who are MDCalc’s partners?

    MDCalc is partnered with several major medical societies and publishers, including the American College of Emergency Physicians, the American Academy of Pediatrics, the American College of Gastroenterology, EB Medicine, and others. You can see a full list on our Partners page.

    About Calculators and Contributors

    Where do these scores come from? Who are the “creators”?

    Clinical scores (equations, algorithms, risk assessments, diagnostic criteria, etc) are based on the best available evidence. By “best available evidence,” we mean data published in a peer-reviewed journal and rigorously studied. As a general rule, we require at least one published validation study in an external cohort to prove the score works.

    A calculator “creator” is an academic researcher who, through intelligent and often complex methods, discovers tools that describe scientific facts about medicine and pathophysiology that can then be applied in practice. These are real scientific discoveries: calcs represent something true about nature, science and medicine. As they are validated by other researchers in new settings and on new patient populations, these tools represent a true discovery about the nature of the human body, which can be invaluable to physicians taking care of patients.

    We include a photo and bio of the “creator” (generally, the first or senior author who first published the paper describing the score) on the calculator page to give them credit for their discoveries and for their important contributions to science and evidence-based medicine. Many “creators” choose to review their photo and bio, and often contribute comments about the calc—if so, it’s marked as such.

    If you are a named author on a score that’s on MDCalc and would like to be credited on the score page, please let us know!

    What does it mean that a calculator has been “Contributed By” and “Reviewed By” someone?

    MDCalc’s Contributors author the content accompanying calcs. Our Contributors tend to be academic physicians practicing clinically who are passionate about EBM and interested in translating evidence into usable bedside tools. We pay Contributors a small honorarium, and over half of our Contributors ask us to donate in their name to their choice of charitable organizations! Reviewers are peer reviewers who check calculator content and calculators for accuracy and clinical relevance. Both Contributors and Reviewers need to meet our conflicts policy. You can learn more and apply at mdcalc.com/contributors.

    Can you add [this score]? How do you decide what gets added to MDCalc?

    We welcome suggestions for scores to add — you can submit a score here (select New Calc Request under Topic). We have hundreds of scores in our pipeline and tend to prioritize those that are clinically useful, published in a peer-reviewed journal, and well-validated (at least in one external cohort from the one it was derived in). Please include a citation or reference when submitting a score. Note that not all scores are accepted for publication on MDCalc.

    How do we know if contributors are biased or have conflicts of interest?

    MDCalc contributors are required to disclose any potential conflicts, similar to contributing to a peer-reviewed journal.

    How many calculators exist?

    There are thousands of “medical calculators” in existence, but not all meet our internal academic robustness threshold to make it onto MDCalc. In the past few years the number of high quality, clinically useful calculators have exploded: in 2013, MDCalc had 80 calculators, and as of 2019 we have over 500, with hundreds of more in our pipeline.

    We hope that MDCalc’s role in helping bring useful calculators to the bedside continues to encourage more academic researchers to create better calculators and improve existing scores, so we may continually provide better care for our patients.

    Using MDCalc

    How do I know if there’s a calculator that’s applicable for my patient / clinical scenario?

    A few years ago we realized that the number of existing medical calculators—now over 500 on MDCalc—means we need smarter ways for physicians to know which calculators exist for their patients. We created a proprietary “discovery” system to help physicians do this, at the bedside. You can now enter your clinical scenario using filters: for example, if you’re concerned about pulmonary embolism and need help to diagnose, choose the filters “pulmonary embolism” + “diagnosis”; if you then diagnose a PE, you can discover a set of new scores that help you prognose and treat the patient by choosing filters “pulmonary embolism” + “prognosis”.

    We have filters based on specialty, organ system, chief complaint, disease, and calc function.

    If there are two calculators for the same purpose, how do I decide which one to use?

    Often there is more than one calc per search for the same purpose; for example, scores for ruling out acute coronary syndromes in patients with chest pain. You can read the key differences between the scores in the descriptions, or in the tabs on each calc page. We’re also starting to have expert contributors write articles to compare sets of similar scores.

    When do calculators work best? Not as well?

    This is very calc-dependent. Our expert contributors aim to highlight this in a very simple and accessible way in the tabs on each calc page, such as in the “Pearls/Pitfalls” tab.

    What’s the best way to explain a calculator’s results to a patient?

    This is often the most challenging aspect of using a calculator! For example, sometimes a score recommends against a CT scan after head trauma, while a patient or family may seem to have the expectation of getting imaging. This is a true test of bedside manner: meeting the challenge of reassuring the individual patient and family through discussion instead of an unnecessary test.

    Such discussions fall closely within a specific study of academic medicine often referred to as shared decision making (SDM). MDCalc is working with some of the top SDM academic experts to build tools that help assist our physicians to have such conversations with patients and families (MDCalc Decision Aids are currently in beta, on the Canadian Head CT Rule and PECARN Head Trauma Rule).

    How do units work?

    MDCalc auto-detects from which country you’re visiting the site (the US, or anywhere else) and determine the correct units for your country by default. You can also change this in your Settings (requires registration, which is free and takes about 30 seconds).

    Where does “Copy Results” copy to?

    “Copy Results” copies the current result into the clipboard, so you can paste into an electronic health record or other note/documentation.

    What browsers are supported?

    We support IE10+ as well as modern browsers such as Safari, Firefox, Chrome, and Opera. Users of IE9- will be directed to our old site (http://old.mdcalc.com/).

    Do you have an app? How is the website different from the apps?

    Yes, we now offer free iOS and Android apps! Check out more about our apps at apps.mdcalc.com.

    Beyond Calculators

    What else does MDCalc offer, beyond calculators?

    In addition to calculators, MDCalc now offers Guidelines and Decision Aids. We also have EHR integrations in development.

    What are Guidelines?

    Guidelines are easy-to-use interactive summaries of clinical practice recommendations. As practicing doctors, we realized that it’s hard to access and use guidelines at the bedside, so we set out to solve this problem with Guidelines, now in beta.

    What are Decision Aids?

    Decision Aids are tools for shared decision making and patient education that are evidence-based and easy to use at the bedside. MDCalc is working with some of the top SDM academic experts to develop these tools to help assist physicians to have conversations with patients and families.

    What is the EHR integration?

    Our EHR integration, MDCalc on FHIR, makes calcs and other MDCalc content available seamlessly through the electronic health record. MDCalc connects medical calculators with patient data through FHIR, writes calculator results back to the patient record, and provides expert content designed to allow clinicians to best use the calculators and clinical decision rules for the individual patient in front of them.

    If you are a hospital administrator and would like to sign up for early access to MDCalc on FHIR, see our EHR page (which includes a contact form).