OSMT (Ontario Society of Medical Technologists) Practice Exam

The reason that Wesley tubes are not used in setting up an Erythrocyte Sedimentation Rate (ESR) test pertains to the standardized methods employed in clinical laboratories for ESR measurement. ESR is traditionally measured using either Westergren or Wintrobe methods, both of which have established protocols with specific tube types designed for accurate measurement of sedimentation over a timed period.

Westergren tubes are wider and longer, allowing for greater sensitivity and precision in measuring the sedimentation of red blood cells in plasma, making them a common choice for ESR testing. Similarly, Wintrobe tubes are also specifically designed for this purpose and offer a reliable method of measuring sedimentation in a shorter timeframe.

Citrated blood is essential to prevent coagulation, ensuring that the sample remains fluid for proper analysis during the ESR test. It works in combination with either of the standardized tubes mentioned above.

Wesley tubes, however, are not recognized or adopted in the standardized protocols for ESR testing. Their design and methodology do not align with the requirements for accurate ESR measurement, which is why they are excluded from the options available for setting up an ESR.