In bacteremia and bacterial diseases, microscopic changes in circulating neutrophils are noted, allowing to suspect the disease, but, of course, do not make a diagnosis. When stained according to Wright, blue or bluish-gray cytoplasmic inclusions — the Taurus Dele, 1-5 µm in diameter, are detected.
They are usually observed in patients with bacteremia, but are not specific. The toxic granularity of neutrophils in the form of tender azurophil granules is often noted in bacterial sepsis, but it can also appear in non-infectious diseases.
Based on the results of some studies of adult patients with bacteremia, it can be assumed that neutrophil vacuolization may be specific for bacterial infections and bacteremia, however, a prospective study of children with fever under polyclinic conditions did not confirm these findings and showed that vacuolation does not have diagnostic value for bacteremia and prognostic with bacterial infections.
In this study, only one of the 7 children with sepsis was tested positive, and only 5 out of 13 children with positive results showed a bacterial infection.
Increased ESR is characteristic of bacteremia or bacterial infection. Based on a study of children with fever on an outpatient basis, McCarthy showed that in patients with bacteremia with ESR above 30 mm / h, this test had 58% sensitivity and 16% specificity. An increase in ESR is also observed in non-infectious diseases, such as inflammatory bowel lesions, rheumatoid diseases, malignant tumors, and viral infections.
Often bacteremia can be detected by examining a Wright-stained smear of precipitated leukocytes, which are located above a column of red blood cells. Positive results are more often observed in patients with asplenia or hyposplenia. The causes of asplenia can be either congenital absence of the spleen, or surgical removal of it.
The hypospace develops in diseases that occur with a lesion of the spleen, for example, in sickle cell anemia. However, the positive results of a smear leukocyte smear study can be obtained in other patients. In Brooke, positive test results were obtained in 3 of 14 patients with bacteremia. According to Faden, bacteria in a smear of precipitated leukocytes were found in 7 out of 10 newborns with bacteremia.
The greater frequency of positive results probably reflects a higher contamination of the organism in children of this age. Information about the sensitivity of this method as applied to the general population of outpatients with fever is absent. Although the study of a smear of precipitated peripheral blood leukocytes has certain advantages and has been shown in some cases, at present it cannot be recommended as a routine screening test.