Sana Zubair¹, Sylvia Ai² 

¹University of Wollongong, NSW, Australia 

²Southern.IML Pathology, Wollongong, NSW, Australia

Aim: To evaluate the effects of delayed blood sample processing and temperature on neutrophil counts. 

Methods: 465 full blood count samples were obtained. 255 samples were stored at 4°C and 210 samples stored at room temperature (22° ± 2°C). Neutrophil count was determined on a Sysmex analyser within four hours of collection, and repeated at 6, 12 and 24 hours post-specimen collection. 

Results: The neutrophil count did not decrease over time for samples in both groups. Neutrophil count showed marginal increase over time, notably in room temperature. 

Discussion: Neutrophil counts remained largely stable suggesting minimal effects of processing delays and temperature on samples up to 24 hours. This is reassuring for laboratories with a large geographical catchment. While the increase in neutrophils was not significant enough to be classified as false neutrophilia, the implications of falsely elevated blood tests can affect diagnostic accuracy and patient management, particular in vulnerable patients whom accurate blood test results are critical for treatment outcomes.  

Key words: "processing delay"; "neutrophil count”; “temperature”, “neutropenia”, “FBC”, “white blood cells”

Contribution: ethics approval, statistical analysis, written report/project