Point-of-Care Testing

For our entire discussion so far, we’ve operated under the assumption that testing happens within the safe, controlled, highly-regulated walls of the central laboratory. But modern medicine moves fast, especially in places like the Emergency Department, the Intensive Care Unit, or the Operating Room. In these settings, waiting 30 or 60 minutes for a result from the central lab can be too long. The clinical need is for a result now

This is the world of Point-of-Care Testing (POCT), which is defined as diagnostic testing performed at or near the site of patient care. Think of it as the “lab without walls.” We are essentially sending small, automated pieces of the laboratory out into the “wild” of the hospital floors and clinics to be operated by non-laboratory personnel, such as nurses, respiratory therapists, or physicians’ assistants

While POCT provides an incredible advantage in speed and Turnaround Time (TAT), it comes with a massive trade-off: we lose direct control. The quality and reliability of a test result are no longer solely in the hands of highly trained Medical Laboratory Scientists. This is why the lab’s role in Quality Assessment and Troubleshooting for POCT is one of the most challenging—and important—jobs we have

Laboratory’s Role: Mission Control

It is a common misconception that because POCT happens outside the lab, the lab is not responsible for it. This is completely false. Under CLIA regulations, the hospital’s laboratory director is ultimately responsible for all testing performed in the institution, regardless of where it happens. The central laboratory, therefore, acts as “Mission Control” for the entire POCT program. Our job isn’t to run the test, but to manage the entire system to ensure it’s safe and effective

Our key responsibilities include:

• Device Selection and Validation: We don’t just let any device into the hospital. The lab is responsible for rigorously evaluating and validating any new POCT instrument to ensure it is accurate, precise, and suitable for its intended clinical use
• Operator Training and Competency: We cannot assume that a nurse or doctor knows how to correctly run a test or perform QC. The lab must develop a comprehensive training program for every single person who will use a POCT device. Furthermore, we must re-assess their competency at regular intervals (typically annually) to ensure they are still performing the test correctly
• Quality Control (QC) Management: This is the core of QA. We are responsible for setting the QC policy. How often should QC be run? What happens when it fails? Modern POCT devices are often “connected,” allowing us to remotely monitor their QC performance. Many have a QC Lockout feature, which the lab programs to automatically disable the device if the required QC has not been performed or if it has failed, preventing a user from testing patients on a faulty device
• Connectivity and Data Management: A result that isn’t in the patient’s chart is a result that doesn’t exist. We are responsible for ensuring the POCT devices can seamlessly and accurately transmit results to the Laboratory Information System (LIS) and the patient’s Electronic Health Record (EHR). This prevents dangerous transcription errors
• Regulatory Oversight: We are the experts in the rules. We ensure the entire POCT program is compliant with all accrediting agencies like CAP, The Joint Commission, and COLA

Troubleshooting in the Wild: Common POCT Pitfalls

Troubleshooting POCT is different because we are often troubleshooting the operator or the environment, not just the device. When a POCT result is questionable, our investigation starts broad

Operator-Related Errors

This is the most frequent source of problems in POCT. Because operators are not dedicated laboratorians, they are more prone to making simple mistakes under pressure

• Incorrect Patient ID: The most critical error. Was the patient’s barcode scanned correctly? Or was the ID manually entered, creating a risk of a typo?
• Improper Specimen Collection/Application: This is a huge issue. For a glucose meter, was the fingerstick squeezed too hard, causing hemolysis or dilution with tissue fluid? For a test cartridge, was it under-filled or over-filled? Was the sample applied too slowly? These small technique errors can drastically alter results
• Ignoring QC or Instrument Prompts: An operator in a hurry might try to bypass a QC failure message or an instrument error flag instead of stopping and addressing the problem
• Incorrect Documentation: If the device is not connected, the result must be manually charted. This opens the door to transcription errors, recording the result on the wrong patient’s chart, or forgetting to chart it at all

Reagent and Device Errors

These are the physical components of the test system

• Improper Storage: Were the glucose test strips left with the cap off, exposing them to humidity and ruining them? Were the test cartridges stored at the correct temperature?
• Expired Materials: This is a constant battle. We must have systems in place to track and remove expired test cartridges and QC materials from all nursing units
• Improper Cleaning: A nurse might wipe down a device with a harsh disinfectant that gets into the measurement area and interferes with the chemistry of the test, causing erroneous results

Quality Control Failures

Our management of the QC program is paramount

• Liquid QC vs. Electronic QC: It’s important to understand the difference. Electronic QC is usually just an internal check of the device’s optical and electronic systems. It does not verify the integrity of the reagent or test strip. Liquid QC is the “gold standard” where a known sample is actually tested, verifying the entire analytical process from sample application to final result. The lab must dictate the appropriate use of both
• Troubleshooting Failures: When a user calls to report a QC failure, our first questions are often directed at the user’s technique. “Can you walk me through exactly how you ran the control?” “Did you use the correct level of control for this device?” “Can you check the expiration date on the vial?”

Ultimately, a successful POCT program is built on a strong partnership between the laboratory and the clinical staff. We provide the expertise, the structure, and the oversight, while they provide the rapid testing at the patient’s side. It’s our job to make sure that the “lab without walls” has a foundation just as strong as the one inside the central lab

Key Terms

• Point-of-Care Testing (POCT): Diagnostic testing performed at or near the site of patient care, outside the physical confines of the central laboratory
• Turnaround Time (TAT): The total amount of time from when a test is ordered to when the result is reported and available to the clinician. The primary goal of POCT is to reduce TAT
• Waived Test: A category of test, as defined by CLIA, that is so simple and accurate that it is deemed to have a negligible risk of an erroneous result. Many, but not all, POCT tests fall into this category
• Operator: Any non-laboratory healthcare professional (e.g., nurse, physician, respiratory therapist) who is trained and authorized to perform POCT
• Competency Assessment: A regulatory requirement where the laboratory must formally evaluate and document that each POCT operator is proficient in performing a test correctly, done upon initial training and annually thereafter
• QC Lockout: A feature of a connected POCT device that the laboratory can program to prevent patient testing if required quality control has not been performed, has failed, or is overdue
• Connectivity: The ability of a POCT device to electronically transmit patient results, QC data, and operator information directly to the Laboratory Information System (LIS) or a dedicated data management system