RBC Clog and RBC Bubbles Flags on Hematology Analyzer

Causes of RBC Clog and RBC Bubbles flags on a hematology analyzer: volumetric measurement principle, count time control, and aperture burn.

Editorial team 2 min August 20, 2024

Diagram of the analyzer's volumetric tube operation during cell counting — Diagram of the analyzer’s volumetric tube operation during cell counting

🤖 Section “Analyzers”❓ Why does the hematology analyzer display the flag: “RBC Bubbles” or “RBC Clog”?

✅ Accurate cell counting is impossible if the exact volume of diluted sample passing through the aperture during the counting cycle is unknown. To control the counting cycle and ensure the analysis of an accurate blood volume, a volumetric measurement unit is used in the hematology analyzer.

✅ With the help of this tube (see diagram below), a precise amount of diluted sample is drawn for measurement during each counting cycle. The precise amount is determined by the distance between two optical sensors. A rinse reagent is used as a delimiter in the measuring tube. The counting cycle starts when the delimiter is at the level of the upper sensor and stops when the delimiter is at the level of the lower sensor. The amount of time required for the delimiter to move from the upper sensor to the lower sensor is called the RBC count time and is measured in seconds. At the end of the counting cycle, the measured count time is compared to a predetermined nominal time. If the measured time is less than the nominal time or exceeds it by 2 seconds or more, the analyzer displays an error message (“RBC Bubbles” or “RBC Clog”).

✅ Causes of “RBC Clog”:

Aperture clogging. 2. Incorrect RBC count time setting. 3. Electromagnetic error.

✅ How to fix the “RBC Clog” error?

Go to the “Service → Maintenance” screen. Perform aperture burn and rinse.
Go to the “Setup → Settings → Count” screen and record the RBC count time. Then go to the “Service → Self-test” screen and check the actual RBC count time according to the instructions.
If the difference between the nominal and actual RBC count time is less than 2 seconds, the problem is resolved. 👉 More details in the Mindray BC-2800 hematology analyzer operating manual.

💎 The complete operating manual for Mindray BC-2800 and other analyzers can be downloaded from the LAB-TESTS library. The link with access to the library is automatically sent to you via private message after paying for a VK donut Labformula subscription.