Hematology analyzers are essential tools in clinical diagnostics, but their results can sometimes be affected by various preanalytical errors. These errors can lead to either erroneous increases or decreases in measured parameters, which may compromise the accuracy of diagnostic information. In the below table, the factors contributing to erroneous results with hematology analyzers are outlined.
| Parameter | Interfering factors | |
|---|---|---|
| Erroneous increase | Erroneous decrease | |
| All parameters | — | Clotted sample |
| WBC count |
|
Clotted sample |
| RBC count |
|
|
| Hemoglobin |
|
Clotted sample |
| MCV |
|
Cryoglobulins |
| MCHC |
|
Very high WBC |
| Platelets |
|
|
| *: WBCs are counted along with RBCs, but normally their number is statistically insignificant | ||
Preanalytical Errors in Hematology
Preanalytical errors in hematology can significantly influence the results obtained from hematology analyzers. One of the most common issues leading to erroneous results is a clotted sample, which can result in decreased values for several parameters such as white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin, and platelets. These errors highlight the importance of proper sample handling and preparation in clinical settings to avoid compromised diagnostics.
Several other factors can lead to erroneous increases in specific parameters. For example, the presence of nucleated red cells, large platelet clumps, or unlysed red cells can cause an artificial rise in the WBC count. In a similar manner, very high WBC levels or giant platelets may lead to an overestimation of RBC count, while hyperlipidemia or elevated bilirubin levels can affect hemoglobin measurements.
Flagging in Hematology Analyzers
Modern hematology analyzers are equipped with flagging mechanisms designed to enhance result accuracy. These ‘flags’ are triggered when abnormal results are detected, indicating the need for further examination. By prompting a review of the blood smear, flags help reduce the likelihood of both false-positive and false-negative results, ensuring that critical diagnostic errors are minimized.