Evaluation of urine dipsticks for quality control of residual erythrocytes and leukocytes in leukocyte-depleted donor plasma

Abstract

Currently used methodologies for quality control of residual leukocytes and erythrocytes in leukocyte-depleted plasma are either expensive or time-consuming. It has been proposed that urine dipsticks could be used as a screening method for residual erythrocytes. The aim was, therefore, to evaluate if urine dipsticks could be used to detect residual erythrocytes and also residual leukocytes in leukocyte-depleted plasma. Dilution series ranging over the decision limits for residual erythrocytes and leukocytes were prepared. Positive, negative and overall agreements, as well as the precision and joint frequency distributions, were calculated for five dipstick analyzers and their corresponding dipsticks. Twenty-four consecutive leukocyte-depleted donor plasma samples were also tested. None of the dipstick analyzers had both a high positive and a high negative agreement. Accordingly, none of the analyzers were able to discriminate between cell concentrations close to the decision limits. The inconsistency count revealed differences in precision between the dipstick analyzers. In the 24 consecutive donor samples, no significant correlation between the dipstick analyzers and the reference methods were found. In conclusion, urine dipsticks are not suitable for quality control of residual leukocytes and erythrocytes in leukocyte-depleted donor plasma.

Keywords:

• Quality control
• transfusion
• red blood cell
• point-of-care testing
• plasma
• practice guideline

Acknowledgments

The expert technical assistance of Odette Tanase, and Sami Alkayyali at the Department of Clinical Chemistry and Transfusion Medicine, Växjö Central Hospital, is greatly appreciated.

Disclosure statement

The authors declare that they have no conflicts of interest relevant to the manuscript submitted to The Scandinavian Journal of Clinical and Laboratory Investigation.

Data availability

The data are available from the corresponding author on a reasonable request.

Additional information

Funding

This work was financially supported by the Department of Research and Development, Region Kronoberg, under Grant 0825-001 4600. Medic24 AB, Siemens Healthcare Diagnostics, Sysmex Nordic ApS, and Zafena AB provided instruments and reagents.