Leukocyte adhesiveness/aggregation test (LAAT) to discriminate between viral and bacterial infections in children

Objectives: We previously noted that white blood cells (WBC) have increased adhesive properties during bacterial infections. Here, we aim to explore t he possibility of using the different adhesive properties of WBC as a means of differentiating between viral and bacterial infections, a common proble m in paediatrics. Methods: The adhesive properties of WBC in the peripheral blood of 25 children with documented bacterial infections, 15 with documen ted viral infections and 36 with probable viral infections, were studied by means of a leukocyte adhesiveness/aggregation slide test (LAAT). The resul ts of the LAAT were compared with those of the other acute phase reactants, namely WBC, differential count and erythrocyte sedimentation rate (ESR), w hich were taken in the same blood sample in each patient. Results: The sens itivity, specificity and positive predictive value were 92%, 96%, and 92%, respectively for the LAAT; 83%, 87% and 80% for the ESR; 56%, 78% and 56% f or the white blood cell count; and 54%, 74% and 50% for the differential co unt Conclusions: The presence of bacterial infections in children can be tested using a simple slide test to reveal the increased state of leukocyte adhes iveness/aggregation in the peripheral blood. The LAAT is a reliable, rapid and inexpensive test, and it can be a useful laboratory tool for the paedia trician treating a child with acute febrile illness.