Lab Follow-up Basics
Route cardiology labs safely — what’s urgent, what’s routine, and how to make sure nothing is dropped.
Learning Objectives
- 1.Recognize the common cardiology labs and why they matter.
- 2.Identify critical values that need urgent escalation.
- 3.Track results to completion so none are dropped.
Purpose
Labs guide medication and safety decisions. A potassium or INR that sits unseen in an inbox can cause real harm. Safe lab follow-up is recognizing what’s urgent and closing the loop.
Labs that matter (and why)
- •Potassium (K): diuretics and ACE/ARB/ARNI shift it; both high and low are dangerous.
- •Creatinine/eGFR: kidney function affects drug dosing and diuretics.
- •INR: warfarin safety — too high = bleeding, too low = clot.
- •Troponin/BNP: ordered for symptoms — never sit on these.
- •Lipids: routine routing, rarely urgent.
- •Digoxin level: narrow therapeutic window.
Critical values — escalate now
- •Potassium <3.0 or >6.0 (or per your lab’s critical thresholds).
- •INR markedly out of range, especially with bleeding.
- •Rapidly rising creatinine / acute kidney injury.
- •Any positive troponin or markedly elevated BNP with symptoms.
Escalate
Critical lab values are time-sensitive. Notify the provider promptly and document the notification — don’t leave a critical result in a queue.
What to document & send the provider
- •The value, reference range, and when drawn.
- •Relevant meds (diuretic, ACE/ARB, warfarin, digoxin) and recent dose changes.
- •Any symptoms; your notification and the plan.
Close the loop
- •Track ordered labs until resulted and acted on.
- •Confirm the patient was notified of changes.
- •Document "left message / spoke with patient" and follow up if no response.
The dropped lab
An abnormal result that no one acts on is a classic safety failure. A reliable tracking system is part of the job.
Patient education script
- •"Your potassium was off, so the provider wants to adjust a medicine and recheck a lab — here’s the plan."
Mini case
A potassium of 6.3 returns on a patient on lisinopril and spironolactone. They feel okay.
What now?
Show answer
Hyperkalemia at 6.3 is a critical value (risk of dangerous arrhythmia) even without symptoms. Escalate to the provider promptly, document the notification, and follow the plan (likely hold/adjust the K-raising meds and recheck) — don’t route it as routine.
Checklist
- Identified urgent vs. routine results.
- Escalated critical values promptly and documented it.
- Noted relevant meds and recent changes.
- Tracked the result to completion and notified the patient.