Point-of-Care Testing
Point-of-Care Testing
The Point-of-Care Testing domain tests waived and moderately complex testing performed outside the main laboratory: glucose meters, INR monitors, blood gas analyzers, rapid strep and influenza tests, pregnancy tests, and fecal occult blood tests. The exam emphasizes operator technique, quality control, documentation, and recognizing when a POC result cannot be trusted.
Core rules
- Perform and document quality control before patient testing according to the facility's policy and manufacturer's instructions, at minimum with each new lot and each day of testing.
- Check strip and reagent expiration dates and storage conditions; do not use strips from a compromised container.
- Code or calibrate the device when required and verify the operator is trained for that device.
- Collect the correct specimen: capillary blood for glucose, fresh venous blood for blood gas, and a properly obtained swab for rapid antigen tests.
- For capillary glucose, wipe away the first drop, avoid squeezing the finger, and apply the drop to the strip without touching it.
- Repeat any critical value with a new specimen and notify the clinician promptly; document the repeat and the notification.
- Record the patient, result, date, time, operator, device, and QC on the report.
Worked example
A glucose meter displays "QC out of range" before a patient test. The operator should not test the patient. First check that the control solution is in date and has been stored correctly, that the strips are not expired, and that the meter is coded properly. Repeat QC with a new strip and fresh control. If QC still fails, remove the meter from service, use an alternative device, and notify the supervisor. Testing a patient with a failed QC could produce a wrong glucose and a wrong insulin dose.
Traps
- Using expired strips because the meter accepted them: falsely low or high results.
- Applying an insufficient blood drop: meter error or inaccurate reading.
- Squeezing the fingertip: tissue fluid dilutes the sample and lowers glucose.
- Reading a rapid strep test after the stated time: false positives from over-reading.
- Failing to document QC: the result is not defensible in an audit or clinical review.