Wednesday, May 15, 2024

by Nitsan Maayan-Rabinowich, Chief Strategy Officer, Sight Diagnostics

Whether you’re planning to establish a moderately complex Physician Office Lab, or you're an experienced practitioner eyeing a new Complete Blood Count (CBC) analyzer for your existing facility, understanding the key factors in selecting the right equipment is paramount. This article is designed to help you navigate the selection process of a CBC analyzer that will align seamlessly with your clinical demands and operational workflows, enabling you to provide superior patient care.

1- Clinical Performance
When integrating a new laboratory device, the top priority is to ensure that it delivers accurate results and meets your specific clinical requirements. While many CBC analyzers might provide precise readings, inferior performances often manifest through a higher rate of invalidations and suppressed results. If results are absent or reported with measurement issues (flagged), local lab policies typically mandate further reflex testing or a smear review. This not only hampers healthcare providers’ ability to make swift clinical decisions, but may also involve sending samples to an external laboratory, which is both costly and time-consuming. Crucially, the lag in verifying lab results delays treatment and heightens patient anxiety. When a CBC analyzer consistently falls short in delivering actionable results (results devoid of invalidations or suppressions), it defeats the purpose of having an on-site lab solution, intended to offer rapid quality care directly at the point of service. Several factors affect the rate of invalidated results, such as the device’s analytical range (reportable and display), its precision in flagging results, the extent of the abnormality flagging menu, and the detail in its white blood cell differential. 

So, how does it work, and why are these factors crucial in affecting a CBC analyzer's effectiveness in producing actionable results? 

Analytical measuring range - this refers to the range of values that the CBC device can accurately measure and report. When a CBC parameter level is outside the analytical range of the analyzer, the result might be suppressed or marked as invalidated. This is a key indicator of the device's analytical capabilities. The challenge with the CBC often lies in accurately detecting lower levels of counts, which are difficult to process, yet crucial to measure, given that such conditions typically involve higher risk and require swift decision-making. Given that CBC analyzers offer varying reportable ranges, dedicating time to researching and determining which device best aligns with your clinical needs and patient demographics is crucial. This approach can markedly decrease the need to send out tests for external analysis. 

Flagging Sensitivity and Specificity: Flagging sensitivity in CBC analyzers refers to the device’s proficiency in identifying and raising a flag to any hematology abnormalities or measurement discrepancies. Conversely, Flagging Specificity refers to the analyzer's ability to correctly identify and flag abnormal results without generating false alarms. The importance of flagging sensitivity is widely acknowledged; it ensures that no significant measurement mishaps or essential clinical inputs slip through the cracks. That said, flagging specificity is crucial as well, as it directly influences workflow efficiency. Inversely, as the flagging specificity rate drops, the incidence of false positives — where normal tests are inaccurately labeled as abnormal—increases. This not only leads to unnecessary reflex testing or manual smears, but also causes delays in treatment and detracts from the cost-effectiveness of the device. For example, a CBC analyzer with a 70% flagging specificity suggests that in 30% of the cases, the analyzer will erroneously signal abnormal results (false positives). This indicates that in 30% of the cases, reflex testing could be avoided. The good news is, that thanks to modern advancements, the market now offers CBC analyzers with a flagging specificity of over 90%, which can significantly streamline your operations. 

The Depth and Specificity of a CBC's Flagging Menu refers to the number of specific flags for distinct CBC abnormalities such as immature granulocytes, nRBCs, atypical lymphocytes, platelets clumps, blasts, and others. A rich flagging menu enhances the analyzer’s ability to identify distinct abnormalities more accurately. The precise identification minimizes the risk of results being invalidated or suppressed by providing clear insights into potential abnormalities rather than broadly flagging results as abnormal. In contrast, analyzers with limited or generic flagging options might lead to the unnecessary manual examination of samples that are not actually abnormal. A rich flagging menu mitigates this by accurately identifying borderline or slightly abnormal results, which may not require further analysis. The bottom line is, when selecting a CBC analyzer for your practice, the number and variety of specificity of abnormality flags it offers should be a key consideration - the more, the merrier. 

The number of white blood cell (WBC) differentials (3 vs. 5 diff) in a CBC analyzer refers to the number of different types of white blood cells the analyzer can identify and enumerate separately. Analyzers with a 5-diff capability offer more comprehensive and nuanced results by distinguishing among a greater variety of white blood cells, thus providing clinicians with deeper insights for accurate diagnoses, differentiating infections from blood disorders, and formulating effective treatment strategies. In contrast, analyzers with limited differential capabilities (3-diff) might lead to incomplete data, requiring additional tests or referrals to specialized external labs, thereby increasing expenses and delaying critical care. While 3-diff analyzers may still be useful for many standard blood count purposes, their limitations in terms of specificity and sensitivity can result in more frequent invalidations and suppressed results compared to the more advanced 5-diff analyzers. When an abnormality occurs in one of the cell types grouped into one category (neutrophils, eosinophils, and basophils), this grouping can lead to invalidations if there are abnormalities in one of these subtypes, as the analyzer cannot specify which type is affected. 3-diff CBC analyzers are estimated to report at least 50% more of the total number of samples generating a suspicious flag than their 5-diff counterparts, ultimately reducing laboratory time and costs related to sample processing and shipping¹ . 

To learn more about a specific CBC analyzers’ clinical performances and features, we recommend you read their latest FDA-510(k) summaries and marketing brochures, or simply ask your sales representative for this information. Additionally, you can find detailed insights in the device’s Instructions For Use or Operators Manual. 

2. Patient Age Applicability

On average, children under the age of one visit their primary care physician four times a year, which is 2 to 4 times more than any other pediatric age group.² Fever ranks as a top reason for medical consultation, while for babies under three months, and febrile, the standard recommendation is an in-hospital observation.³ For children older than three months, it’s typically recommended that they initially visit a primary care physician before heading to the emergency department.⁴ A CBC with a differential, or at a minimum a WBC count, is advised for  children with fever.⁵ Moreover, the American Academy of Pediatrics (AAP) recommends CBC screening for anemia in the 9 to 12 months age bracket,⁶ as adequate iron stores are critical for normal cognitive development. Therefore, if you provide or plan to provide care to pediatric patients, ensuring your on-site CBC device is suitable for children aged three months and older is essential.

3. Blood Collection Method Options

For those treating pediatric patients, it’s widely recognized that up to a certain age, using capillary blood for a CBC test is far more convenient than a venous draw. The capillary method is easier to collect, requires a smaller blood volume, and is less intimidating and painful for both the patient and their caregiver. Capillary sampling is also an appealing option for populations where conventional sampling methods face difficulties, such as elderly, psychiatric, and oncology patients.

Until recently, finding a tabletop CBC analyzer that was FDA-cleared for capillary blood testing was nearly impossible. Nowadays, there are several new technologies that are FDA-cleared for CBC capillary blood testing via a tube or directly from the finger. 

4. Eligibility for Individualized Quality Control Plan (IQCP)

If your facility already operates laboratory equipment, you’re probably well-versed in the rigorous quality control and result verification procedures mandated by the Clinical Laboratory Improvement Amendments (CLIA). Typically, you probably spend considerable daily time on quality control procedures, documentation, results review, and related tasks. Imagine reallocating this time towards activities that generate more value or avoiding the inconvenience of informing a patient that their test cannot be conducted because the device is undergoing its daily quality control. The good news is that this is now achievable for a select number of CBC analyzers through the implementation of an Individualized Quality Control Plan (IQCP).⁷ IQCP is a tailor-made quality control strategy endorsed by CLIA for devices with advanced and robust internal controls that ensure consistent performance and calibration over time. By implementing an IQCP, you can significantly cut down the daily QC procedures from once a day to a few times a month, saving time, money, and energy while still adhering to compliance measures. Since this option is available with only a limited number of devices, the best way to determine whether a CBC device is eligible for IQCP is to ask your sales representative.       

Device Cleaning and Maintenance

Have you ever wondered how much time you and your team dedicate to cleaning and maintaining your CBC analyzer? From daily startup and shutdown cleaning through weekly flush tubing, reagent replacement, and aperture cleaning to monthly tubing replacement, not to mention regular internal component cleanings and preventative maintenance checks, these tasks, while essential for the accurate operation of liquid reagent-based CBC analyzers, are notably time-consuming and exhausting.

 Fortunately, cartridge-based CBC analyzers, free from liquid reagents, present a solution to these exhaustive procedures. This new generation of devices utilizes single-use, disposable test kits containing a cartridge and everything required to perform the CBC test. Unlike liquid reagents, these kits have a long shelf life and do not require special storage conditions. The device itself contains no tubes or reagents, so traditional cleaning or maintenance virtually disappears, freeing up your team to focus on what matters most — delivering quality, efficient patient care without the burden of non-essential tasks. 

Summary

Choosing the right CBC analyzer involves a careful evaluation beyond just clinical performance, such as analytical precision, flagging specificity and menu richness, and WBC differential count. It’s equally important to consider operational aspects, like the ease of maintenance, IQCP eligibility, adaptability to various age groups, and blood collection techniques. The objective is to select a device that not only ensures accurate and timely results but also seamlessly integrates into your practice's workflow, thereby elevating the standard of care provided.  

References:

1. “Hematology analyzers: 3-part or 5-part, that is the question”, Boule.com, 2019
2. “Primary Care  in the United States: A Chartbook of  Facts and Statistics”, Robert Graham Center, February 2021
3. ”Fever in children: pearls and pitfalls”, Barbi E, Marzuillo P, Neri E, Naviglio S, Krauss BS,  , Pubmed Central, September 2017
4. A fever is rarely a reason to go to the hospital — here's what to do if you or your child has a fever”, Business Insider, December 2020
5. “Fever Without a Focus Workup”, Muhammad Waseem, Medscape, June 2023
6. “Clinical Report—Diagnosis and Prevention of Iron Deficiency and Iron-Deficiency Anemia in Infants and Young Children (0–3 Years of Age)”, Robert D. Baker, MD, PhD, Frank R. Greer, MD, and THE COMMITTEE ON NUTRITION ,American Academy of Pediatrics, 2010
7. Individualized Quality Control Plan (IQCP) | CDC