Body Fluids Analysis with Linearity Down to Zero

Why Test Body Fluids?

Body fluid analysis is a challenging task for most labs because the samples—such as cerebrospinal, synovial, pleural fluid, pericardial, peritoneal and general serous fluid are difficult to draw-- not to mention a discomforting experience for the patient.

However, it’s an imperative part of diagnosis, as fluid analysis assists in the identification of certain disease states including meningitis, hemorrhage, malignancy, inflammation, viral, bacterial/parasitic infections and more. Because urgent diagnostic data is often sought after from even a very limited sample for the diagnosis of these disease states, accuracy and speed of results take on even greater importance.

For this reason, laboratories have traditionally resorted to manual body fluid cell counting to ensure the highest quality of insights. However, lately there’s been a shift to an automated approach, including analyzer-based body fluid analysis.

How Body Fluids are Analyzed

Body fluid analysis is performed in one of two overall ways: manual cell count using a hemocytometer and an automated approach using an automated analyzer.

While manual counting is the gold standard, there are numerous downsides to the process, as it is time consuming, taking at least 30 minutes to an hour to perform a total RBC and WBC count. Manual review requires a well-trained, licensed personnel due to the testing complexity.

It’s also a subjective approach where competency and technique of testing personnel are not always consistent. Lastly, it’s a labor-intensive process because it requires the staff's full attention and they are unable to perform any other tasks.

After all this manual work, results must be calculated by hand and this can potentially cause clerical and mathematical errors-- even with the use of a calculator.

How Automated Body Fluid Testing is Different

Automated counting removes many of the variables involved with manual review. Foremost, it’s time saving because it takes about five minutes to perform the total RBC and WBC count. It’s moderately complex to perform and can be done by any licensed personnel.

It also reduces the potential for user subjectivity and requires minimal labor. Unlike manual counting, it increases productivity of testing personnel and frees up staff so that they can perform other laboratory tasks.

There are three methods to automated cell counting:

• Method 1: Enhanced Impedance counting is available on some hematology platforms and relies on the displacement of electrical field to provide information on particle size and volume. This aids in classifying particles.
• Method 2: Simple Flow Cytometry measures cell granularity, size and light scatter. This can be performed on some hematology platforms. The laser detects size, volume and shape that aides in classifying particles.
• Method 3: Particle and Image Recognition used by instruments like the iQ200 automated urine microscopy analyzer. The cells are counted by digital flow morphology, allowing the system to capture actual images of particles and classifies by size, shape, contrast and texture. A visual inspection by a technician can be done after analysis is complete, if they need to identify real cells from artifacts.

Do Different Automated Methods Have the Same Functional Sensitivity?

The functional sensitivity for the above-mentioned methods is not the same. For example, in Method #3, the particle and image recognition method offer low count sensitivity and linearity. It can even go down to zero for RBC and WBC.

Also, limitations at the zero of low count range narrows the application of automation for all types of body fluids, particularly clear/colorless CSF. Normally, counting this kind of fluid can only be done by the labor-intensive manual method or by using the iQ200 automated analyzer (Method #3).

However, all the listed automated methods are far less subjective and produce faster results than the gold standard manual method by removing the need for manual counting.

Additionally, when using an automated approach, body fluids with very large cells or cells clumped together like tumor cells cannot be accurately counted by the first two methods. They can be identified by the iQ200 automated analyzer (Method #3) due to the instrument’s ability to identify and capture images of particle during the analysis. iQ200 technicians visually inspect particle images, and when they see very large or clumped tumor cells on the iQ200, the technician is alerted to check test results in hematology for these cells when performing WBC differential counts.

Below is a summary of the benefits of an automated approach when it comes to testing body fluids versus a manual approach:

Source: Body Fluids Analysis with Linearity Down to Zero Webinar, 2017.

Better Body Fluids Analysis with Automated Urine Microscopy Analyzer

For laboratories looking to reduce manual work associated with manual review, there is a better solution. The iQ200 series automated urine microscopy analyzer can provide digital images and shorten turn-around-time with standardized results.

With the optional Body Fluid Module, laboratories can be empowered with a complete body fluids menu and on-screen particle isolation. Some of the benefits of the Body Fluids Module with use of synovial fluids are listed in the table below:

Source: Body Fluids Analysis with Linearity Down to Zero Webinar, 2017.

According to Pat Guinane, MT(ASCP), core laboratory supervisor at Arnot Ogden Medical Center in Elmira, New York, there are a host of benefits to digital flow morphology for body fluids as opposed to using a hemacytometer. The most notable being improved day-to-day workflow.

"Digital flow morphology for body fluids analysis is a win-win situation," Pat said, "before the iQ200, we performed most body fluids on our hematology analyzer, except synovial fluids – which were manual counts due to the viscosity of the specimen. Many times, they were below linearity of the hematology analyzer so we would end up doing manual counts." Pat pointed out that body fluids often arrive at inconvenient times. "For example, during shift change, as well as the off-shifts," she noted. "The iQ200 has streamlined our workflow immensely during the off-shifts."

In practice, Pat has also achieved standardization of body fluid counting and resulting by using the iQ while minimizing tech-to-tech variation. "It’s what the iRICELL does, it’s almost the definition of the Iris," she noted.

The iQ200 has also greatly improved turn-around-time for body fluids results in this laboratory, according to Laura Wintjen, CLS (ASCP), core laboratory lead technologist at Arnot Ogden. "This has freed techs up to do other tasks within the lab," she added.

Overall, using the body fluids module improved employee satisfaction by reducing time spent at a microscope. "Everyone would agree that the Iris has really been a game changer," Pat said. 

While Argot Ogden’s lab has experienced stable volume since automating, it's affiliated with Lake Erie College of Osteopathic Medicine and sometimes ordering habits of physicians are not consistent. Therefore, it does make it easier to keep up with varying numbers of orders, especially when it comes to body fluids.

Physicians are also happy with getting a low and accurate count on their body fluids and if there is question regarding any data, medical technologist can easily pull them up and review the images. "This is also beneficial regarding competencies," Laura said. “If the image is reviewed due to a doctor’s request and it's correct, we can use that for a competency of the tech."

Lastly, the benefit of images on the iQ200 is especially helpful. "Images are always the same, you don’t have to worry about lighting and the diaphragm." Laura explained. "There are no problems with refraction due to improper illumination or plane of focus."

Images also help with streamlining training and competencies with techs. "We don’t have to wait for certain crystals or other infrequent sediment to show up in order to get techs proficient in the identification," Laura said. "We do a monthly check of body fluids on the instrument to look at any abnormal cells and randomly select staff to review for identification of competencies."

Images are also useful in comparing discrepancies when a physician may call and question results. The images can be pulled up and verified or amended as well as follow-up with techs.

All in all, there are numerous benefits to automating body fluid analysis. It is one sure way to simplify a challenging task that is an essential part of diagnosing very serious medical conditions. Since urgent diagnostic data is often sought after from even a very limited sample for the diagnosis of these disease states, accuracy and speed of results take on even greater importance. Learn more about streamlining the process in your lab with our automated body fluids solution and move your body fluid microscopy forward.