12.2 Waived/POC QC, Result Evaluation & Reporting

12.2 Waived/POC QC, Result Evaluation & Reporting

Quick Answer: Run QC as the manufacturer and SOP require. Fail QC → stop patient reporting on that system until fixed. For lateral-flow kits, respect the read window; late or early reads are invalid. Document results with correct patient, time, units (e.g., mg/dL), and operator; escalate critical glucoses immediately. Never change timing to force a line or number.

Quality control and result handling complete Domain III G. Waived and Point-of-Care Testing. Operation without QC discipline produces numbers that look precise and are clinically dangerous. MLA exam items often hinge on the single correct action after a failed control or an invalid cassette.

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Internal QC vs External Liquid QC

Manufacturers use different QC designs. Know the vocabulary:

Both may be required. A visible control line on a pregnancy cassette does not automatically replace external liquid QC if your SOP or insert still mandates liquid controls at defined intervals.

Typical QC triggers (follow your IFU/SOP)

• New lot or new shipment of strips/kits
• New operator (as policy requires)
• Daily or per shift for high-use meters
• After maintenance, battery change, or dropped device
• When patient results are unexpected or inconsistent with clinical status
• When the device prompts for QC or locks out testing

Record QC results in the log, middleware, or LIS as required—who, what device, lot numbers, expected ranges, pass/fail, corrective action.

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Fail QC → Do Not Report Patient Results

This is a hard stop, not a suggestion.

If QC is out of range or fails:

1. Do not release or act on new patient results from that device/kit lot until the issue is resolved.
2. Repeat QC only if the SOP allows a single repeat for technical error (wrong level used, expired control, incorrect temperature).
3. Troubleshoot systematically: expired controls, incorrect storage, wrong control level, dirty meter, mismatched strip lot/code, degraded strips, user technique.
4. Open new controls or strips only as directed; do not chase a pass by testing every bottle in inventory without documentation.
5. Remove the device from service or quarantine the kit lot if failures persist.
6. Document failures and corrective actions; notify the POC coordinator, charge tech, or supervisor per policy.
7. Resume patient testing only after required QC levels pass and any lockout is cleared.

Results already reported before a QC failure was discovered may need look-back review by laboratory leadership—flag the event; do not hide it.

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Lateral-Flow Read Windows and Invalid Tests

Many waived kits are immunochromatographic (lateral flow) devices: sample migrates along a strip; lines appear in test (T) and control (C) regions.

Read window rules

Never:

• Hold a cassette longer “to make the line darker”
• Use a phone flashlight and imagination to call a faint late line positive after the window closed
• Report results from a device that flooded, ran improperly, or shows a defective migration front

Invalid test actions

1. Label the run as invalid (not negative).
2. Repeat with a new kit and correct technique/sample.
3. If repeats remain invalid, stop, check storage/lots, and escalate—consider alternative method or send-out to the main lab per protocol.
4. Document invalids so quality trends are visible (shipping damage, humidity, training gaps).

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Evaluating Device Results (Meters and Analyzers)

Electronic POC devices may display:

• Numeric results with units
• Error codes (sample too small, temperature, strip expired, QC due)
• Hi/Lo or above/below reportable range flags
• Critically high or low prompts (especially glucose)

MLA evaluation checklist:

1. Was QC in for this device/lot?
2. Was the sample type and volume correct?
3. Is the result within the device’s reportable range?
4. Does the value make clinical sense enough to report (or is it a possible wrong patient / wrong technique)?
5. Are units correct and consistent with orders and charting systems?

If the meter says “error” or “repeat test,” do not invent a number. Collect a new sample or follow the error-code table. Extremely high glucose readings may require confirmation per policy (repeat, serum lab glucose) before some therapies—know your critical and confirmation rules.

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Documenting and Reporting Results

A waived result that is not documented under the right patient might as well not exist—or worse, may exist on the wrong chart.

Include as required by SOP:

• Patient two identifiers / accession
• Test name and result with units
• Date and time of collection and testing (if different)
• Operator ID
• Device ID / serial and reagent lot when required
• Reference range or interpretive guide if the system provides one for that method
• Comments for hemolyzed, QNS, refused, invalid, or repeated testing

Enter results into the LIS, EHR, or approved log only through authorized workflows. Verbal reporting (when allowed) still needs read-back of patient identity and result, then chart documentation.

Unit consistency: glucose and mg/dL

In U.S. clinical practice, blood glucose is almost always reported in mg/dL. Some international literature and some meter modes use mmol/L. The MLA must:

• Confirm the meter is set to the facility’s units
• Never assume a number in mmol/L equals the same number in mg/dL (rough conversion: mmol/L × 18 ≈ mg/dL)
• Watch for transcription errors when copying results between systems

Mis-unit reporting can cause 18-fold dosing mistakes—treat unit checks as critical.

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Critical Glucose Escalation

Hypoglycemia and severe hyperglycemia are time-sensitive. Facility critical value lists define numeric thresholds (examples vary by age and site—always use your policy, not a memorized single number from a textbook).

MLA responsibilities typically include:

1. Recognize a result that meets critical criteria or device “critical” flags.
2. Repeat only if policy requires confirmation before notification (some sites notify on first critical POC glucose while arranging lab confirmation).
3. Notify the responsible licensed caregiver immediately (nurse, provider) using the approved chain—not a sticky note hours later.
4. Document who was notified, time, read-back, and the result with units.
5. Stay with the patient care team’s process for treatment monitoring (e.g., recheck after intervention) per orders.

Do not leave a critical glucose on a printer tray, in an unfinished chart note, or only in meter memory.

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Never Modify Timing to Force a Result

Exam and real-world integrity rule:

Altering timing, diluting samples without authorization, or re-dipping strips to “improve” color are result falsification pathways. Report honest invalids and delays.

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Connecting QC to Broader Lab Quality

Waived/POC QC is the same quality culture as main-lab QC (Chapter 10 concepts), scaled to simple methods:

• Controls must be in range before trusting patients
• Trends (slow drift of meter bias, rising invalid rates) need escalation, not silent workarounds
• Competency failures show up as QC fails and invalids—retrain

When POC results disagree with central laboratory results, help leadership gather lots, times, devices, and technique—do not automatically discard either result without investigation.

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Quick Scenario Drill (Mental Checklist)

1. Patient ID complete?
2. Kit/meter in date, stored correctly, cleaned?
3. QC current and passing?
4. Technique and timing per IFU?
5. Result valid (control line, no error, in window)?
6. Units and documentation correct?
7. Critical pathway triggered if needed?

If any answer is no, stop and fix before the result drives care.

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