Two-person check
Rehearse an independent double check.
Practice the habit with a classmate on fictional problems. One of you shows an answer as a QR code. The other scans it, works the problem without seeing that answer, and enters their own. Their device compares the two and shows the result.
It is a drill for learning. It is not a clinical verification record, and it does not replace any institution's double-check process.
What makes a check independent
A double check is independent when two people work the same problem separately, and neither knows the other's answer until both are done. Someone who already knows the expected answer tends to see it, even in work that has an error. Working blind takes that pull away.
ISMP, the Institute for Safe Medication Practices, describes the independent double check this way. It also recommends using it selectively, for chosen high-alert tasks, rather than for everything, and sets out how to carry one out.
Drug Infusion builds the blind part into the drill: the person checking never sees the first answer before entering their own.
ISMP: Independent Double Checks: Worth the Effort if Used Judiciously and Properly (opens in a new tab)
Show, scan, check
Show
Work a fictional rate problem in the calculator, tap “Verify this calculation”, then “Two-Person QR Verification”. Your answer appears as a QR code.
Scan
Your partner opens the Verify tab and scans the code with their camera, then confirms the problem's details on their own screen.
Check
They work the problem themselves and enter their rate. Your answer is not shown to them first. Their device compares the two and shows the result.
What a match means
There is no percentage band. The app rounds the rate in the code to the decimal places the verifier typed, and the two must then be identical. If the code holds 13.69 mL/hr, an entry of 13.7 matches and 13.6 does not.
Each size of rate has a minimum number of decimal places, and the app never compares more coarsely than that minimum for either rate. If the entry has fewer decimal places than its size needs, the app asks for a more precise number instead of judging it, and the request gives no hint of the answer. An entry of zero or less never matches; the app asks for it again.
In a drill, a mismatch is useful: work the problem again together and find where the two setups part.
What it is not
- Not two-way.The check is one-way: the result shows only on the verifier's device. The screen that showed the code is not a record of the check, and nothing is sent back to it.
- Not proof of who made the code.Each code carries an integrity code from a key built into the app, so a damaged or altered code is rejected before any of its details are shown. That makes tampering evident; it does not identify the sender, and anyone with the app can make a code.
- Not for every answer.Only rate answers in mL/hr can be checked. Bolus and dilution answers can't be shown as a code.
- Not across versions.Both devices need the same version of Drug Infusion. Each code records the drug database it was made with, and the verifier's device rejects a code made with a different one.
- Not open-ended.A code expires after 10 minutes, and a code dated too far ahead of the verifier's clock is rejected as well.
- Not repeatable on one device.Each code can be checked once per device: scanning the same code again on that device is refused. That record stays on the device; it is not shared with other devices.
- Not an institution's process.It is a drill for learning on fictional problems. It does not replace any institution's double-check policy, and its result is not a clinical verification record.
Free and Pro
Receiving a check is always free and unlimited, so your partner never needs Pro to check your answer.
Starting a check, by showing your answer as a code, is free 5 times, for life. After that, starting checks needs Pro, a one-time purchase (US$29.99 in the US).
Run a drill with a classmate
Five steps, on a fictional rate problem you both have in front of you.
- Pick a fictional rate problem with an answer in mL/hr, from a worksheet, a textbook or a Scenario you built, and check that both devices run the same version of Drug Infusion.
- Partner A works it in the calculator and shows the answer as a QR code. Partner B works it on paper, without looking at A's screen.
- Partner B scans the code within 10 minutes and confirms that its details match the problem in front of you.
- Partner B enters their own rate. If the app asks for more decimal places, B takes them from their own work, never from A's screen.
- Read the result on B's device. On a mismatch, rework the problem together until you find the difference. Then swap roles and try the next problem.
What the code carries
- It works offline: no network, Bluetooth, Wi-Fi, NFC or pairing. The only transfer is light from one screen to the other device's camera.
- The code holds the practice problem's details, such as the generic drug name, the concentration, the bag volume, the dose, a practice weight when the problem uses one, the calculation mode and the proposed rate, plus integrity and version data.
- It holds no person's name or identifier, no health information, no location, no persistent device identifier, no calculation history and nothing about you. The only ID it carries is a random code ID, which the verifier's device keeps with the result and uses to refuse a repeat scan.
- Camera is the only permission it uses. Frames are processed on the device, and no image is saved or sent.
- The verifier's device keeps the outcome in its Activity Log (Settings → Activity Log), on the device only. Nothing is uploaded.
Try it with a classmate.
Drug Infusion is free to download. Receiving checks is unlimited, and each of you can start 5 for free.