Write down and read back first
At 14:00 the laboratory staff calls with a critical serum potassium result, and the caller is still on the line. The first action is to write down the result and read it back to the caller before the call ends, so that any error is caught at its source. A potassium value misheard by a single digit could lead to giving or withholding treatment wrongly, with dangerous effects on heart rhythm. Read-back is a form of closed-loop communication: the receiver repeats the information and the sender confirms it is correct.
What follows the read-back
Once the value is confirmed, the nurse reports it promptly to the responsible provider, assesses the client for related signs such as muscle weakness, arrhythmias, or changes on the cardiac monitor, and documents the result, the time it was received, the name of the caller, who was notified, when, and any orders received. Many hospitals set a time limit for reporting critical results to the provider. The order of actions matters: confirm, report, assess, and document, with assessment often happening alongside reporting.
| Action | When | Reason |
|---|
| Write down and read back | First, while caller is on the line | Catches errors at the source |
| Report to the provider | Next, promptly | Treatment depends on the provider |
| Assess the client | With or after reporting | Identify related signs |
| Document | After confirming and reporting | Record time, caller, notification |
Why the other actions are not first
Calling the attending physician right away is important, but reporting an unconfirmed value risks passing on an error. Recording the time received is part of documentation, which follows confirmation and reporting. Assessing the client is appropriate, but once the caller hangs up, the chance to confirm the value directly is lost. The read-back takes only seconds and protects every later step.
Link to communication safety
Read-back is required for verbal and telephone orders and critical test results in many safety standards. For this client after an ischemic stroke, the potassium result may relate to medications such as diuretics or to intake; either way, the provider needs the correct value.
Exam takeaway
Key point Critical result by phone: write it down and read it back before the call ends, then report, assess, and document.