Since Congress passed and the president signed The Patient Protection & Affordable Care Act (PPACA, or ACA) in 2010, the law has been, to put it mildly, a significant contributor to the ongoing national conversation about healthcare costs, quality, and delivery. The ACA affects all areas of healthcare, and the clinical lab is no exception.
The primary goals of healthcare reform include increasing access to healthcare, improving the quality of care, lowering costs, and increasing accountability and efficiency. In the future, hospitals will be paid according to a Value Based Purchasing model, which is a payment model linking reimbursement to performance based on a set of quality metrics such as a reduction in infections and readmissions.
Pressures to lower costs and improve efficiency are not new concepts for the lab. Lean and Six Sigma principles have been implemented over the years to standardize and streamline workflow. With healthcare reform and the expected increase in the number of insured individuals, labs will be challenged to undertake the analysis of more samples with prompt turnaround times. Metrics such as urinary tract infection prevention may call for labs to handle a higher volume of urinalysis testing. For this reason, labs may find it beneficial to upgrade their current urinalysis method to a fully automated system.
Technology: the new options
Historically, urinalysis has been a manual, labor-intensive set of procedures. It wasn’t until the 1970s that the first semi-automated urine chemistry strip reader became available. Strip readers standardized the interpretation of results, improving consistency, accuracy, and precision. Interface capability for LIS connectivity made semi-automation even more desirable by reducing the potential for data entry errors. Microscopy was still a manual process until the 1980s and 1990s, when digital imagery and flow cytometry were introduced for automated urine microscopy. Today, there are fully integrated urinalysis systems that combine automated chemistry with automated microscopy for true walkaway capability.
Many labs are already using an automated chemistry system and are now looking to replace their manual microscopy with an automated solution. Automated sediment analysis is accomplished through one of two technologies: flow cytometry or digital imaging.
Flow cytometry removes the vast majority of operator-to-operator subjectivity from sediment analysis. A polymethine dye targeting protein and nucleic acid is added to a pH adjusted sample in a heated reaction chamber. Sample from the reaction chamber is injected into the flow cell. Hydrodynamic focusing aligns particles into single file so each particle can be explored by laser light. Detectors collect light scatter and fluorescence properties which differentiate the formed elements when plotted on a dual parameter cytogram. RBC, WBC, squamous epithelial cells, hyaline casts, and bacteria are enumerated. Pathologic casts, yeast, sperm, crystals, and abnormal epithelial cells generate a flag when a negative threshold is exceeded, allowing a focused confirmation by manual microscopy. Flow cytometric systems analyze approximately 8.8µl of sample, equivalent to about 44 high power fields.
Advocates of flow cytometry point to several strengths of the technology. Proprietary immunofluorescent dyes target nucleic acid for a specific and sensitive bacteria count. Some studies of flow cytometry analyzers showed a 99% negative predictive value (NPV) for culture. The instrument incorporates a preset anti-carryover rinse for high bacteria counts to ensure an accurate and reproducible bacteria result.
Digital imaging systems utilize a flow cell, strobe lamp, and digital camera along with software to classify and quantitate cells and formed elements in uncentrifuged urine. Approximately 500 images per sample are collected as the software classifies particles into categories including RBC, WBC, WBC clumps, hyaline casts, pathological casts, squamous epithelial cells, non-squamous epithelial cells, bacteria, yeast, crystals, mucus, and sperm. A trained operator reviews and manually reclassifies representative images as needed, using an elaborate review process flow diagram. A manual microscopy evaluation of the sample may be needed to confirm certain particles.
Digital imaging analyzers require the operator to review the background of images for particles resembling bacteria and then adjust the bacteria result according to what they observe. Some users report that they find this challenging to standardize across many operators, as it is subjective and only as good as the quality of the image.
What to consider
Upgrading is not an easy decision, and it can feel overwhelming. A new system brings questions:
1. How does the technology work, and is it reliable?
2. How will it affect the workflow and current efficiency in the lab, in terms of
- time to load strips and quantity that can be loaded
- time to review images on a screen and/or go back to a microscope for confirmation
- time for general instrument maintenance (daily, weekly, monthly)
- length of time to train staff?
3. What is the learning curve and level of expertise needed to accurately run an automated system?
4. Will the lab require a major renovation to fit the instrument into the lab space?
The learning curve is very important, and this consideration can sometimes be overshadowed in the process of upgrading. It is important to remember that if it takes an operator weeks to become an expert on the system, then that person is not available to support ongoing laboratory needs; the lab needs to add staff to work while that person is training. It is critical to obtain information from the instrument manufacturer on how long it takes to become competent to operate the system. The flow cytometry systems in the market are very similar to hematology systems. The operators do not need to learn how to edit and reclassify images. No operator intervention is required; either the sample is flagged for review or not. If the sample is flagged for review, the operator will review at the scope where there is already a high level of competency.
Additional features to consider when upgrading are:
- Is a consolidated report readily available?
- Does the software have the ability to perform reflex testing (i.e., if the dipstick is positive for protein, nitrites, leukocyte esterase, and/or blood, will the instrument automatically complete a sediment analysis)?
- What are the limitations of the measurement range?
Another very practical attribute of any instrument is size. A strip reader and microscope take up relatively little space. Fully automated systems measure between 31.5 inches wide for the smallest in the market up to 63 inches. In addition to considering the cost of the instrument, the lab must assess the costs of installing a system, especially when bench space is limited. The cost and timeframe to build out additional space can be very expensive.
Automation at the urinalysis bench has the potential to aid the clinical laboratory in achieving quality metrics for incentive payments. Labs can lead the way to smarter, more cost-effective testing by evaluating urinalysis automation as a tool for reducing the number of urine cultures. Fully automated urinalysis provides the ability to streamline workflow and create a high level of standardization for the lab. As they plan for the future, lab directors are looking for an automated system that is accurate and efficient, and that standardizes workflow, fits in the desired lab space, and has a high level of bacteria detection. They also are keeping in mind the over-arching objectives of automation in the clinical lab: to lower costs, increase efficiency, and help improve the quality of patient care.
