Flow cytometric white blood differential using CytoDiff™ in the diagnosis of neonatal early-onset infection

Neonatal early-onset infection is a life-threatening disease, requiring early diagnosis and treatment. Newborns at risk are identified by a combination of risk factors, clinical signs of infection and laboratory parameters such as white blood cell count and C-reactive protein (CRP). This method is labor-intensive, time consuming and has a variable reproducibility. New reliable diagnostic markers are needed to identify neonatal infection. This study presents additional leukocyte differential parameters produced by the automated flow cytometry and processing software using CytoDiff™ reagent (Beckman Coulter) in newborns suspected for early-onset infection.

An analytic prospective observational case-control study was performed in which 185 newborns were included and retrospectively allocated into two groups, "infection likely" and "infection unlikely". Leukocyte parameters of the CytoDiff™ technique were compared with microscopic slide differentiation and routine tests.

We showed significant lower numbers of monocytes, CD16(-) monocytes and lymphocytes (including T+/NK-lymphocytes) in neonates suspected for early-onset infection using CytoDiff™ technique. The manual counting did not demonstrate changes with respect to the number of monocytes in these neonates.

The automated routine CytoDiff™ leukocyte differential provides an interesting additional diagnostic tool, next to routine laboratory diagnostics, in the diagnosis of neonatal early-onset infection.