Although leukocytosis is a predictive sign in patients with Clostridium difficile (c difficultinfection, it is not an independent predictor of a positive nucleic acid amplification test (NAAT) result for hospitalized patients, according to study results published in Clinical Infectious Diseases.
In this retrospective cross-sectional study, researchers reviewed the data of 16,568 consecutive patients from 4 hospitals over a 4-year period to determine whether leukocytosis was positively associated. c difficult NAAT results. Leukocytosis was defined as an elevated white blood cell count (WBC) that was greater than 15 A/μL. All patients underwent WBC and NAAT testing on the same day.
The majority of patients are men with an average age of 60 years. 74% (n = 12,290) were inpatients, 15% (n = 2507) were outpatients, and 11% (n = 1771) were in the emergency department (ED). A total of 1681 patients were diagnosed c difficult And the remaining 14887 were negative c difficult.
WBC was not predictive of c difficult Status among patients in the NAAT-positive versus NAAT-negative groups. Furthermore, NAAT positivity rates were similar for patients with leukocytosis (11% vs 10%, respectively).
Receiver operator characteristic curve analysis found no difference in WBC between NAAT-positive and NAAT-negative inpatients. However, WBC was statistically higher in NAAT-positive patients between outpatients and patients in ED with limited predictive value (area under the curve, 0.59 and 0.56, respectively).
In a stratified subgroup analysis for the presence or absence of different c difficultRelevant clinical factors (diarrhea, abdominal pain, fever, positive bacterial culture, previous exposure to antibiotics, and other diagnoses associated with leukocytosis), WBC was not predictive of a positive NAAT outcome in any hospitalized patient.
However, in a subgroup of outpatients and patients in ED (n = 1084), the WBC predicted a positive NAAT result with a receptor operator distinct area under the curve of 0.63 (95% CI, 0.57%-0.69%) for the following 3 clinical manifestations: diarrhea, Negative or no bacterial culture, and no exposure to antibiotics within 4 weeks. Within this subgroup, NAAT positivity rates were 16% in those with leukocytosis and 9% in those without leukocytosis.
Consistent with previous studies, the study authors noted that hospitalized patients with high WBC and positive NAAT results “have longer inpatient stays and a higher likelihood of in-hospital death, although there is a greater likelihood of treatment with metronidazole or vancomycin.” At the same time, compared to inpatients with low WBC, inpatients with high WBC and negative NAAT results had higher stool frequency (s <.001), a longer hospital stay (19 vs. 10 days; s <.001), and higher mortality (relative ratio, 1.9; 95% CI, 1.7%-22%; s <.001).
Thus, regardless of c difficult The study authors said that patients with leukocytosis had the opposite outlook.
Not only did leukocytosis have low specificity, considering that the leukemoid reaction was not specific. c difficult infection, it also had a low sensitivity, as 46% of patients with a positive NAAT result had a WBC within the normal range. Leukocytosis is not an independent predictor of c difficult NAAT status, especially among inpatients, and should not be used in isolation as a justification c difficult test,” concluded the study authors.
Disclosure: Several study authors have stated their association with the pharmaceutical industry. Please see the original reference for a full list of author disclosures.
Bosch D, Matthias PC, Crum N, Brian A, Fang FC, Grainger L. An elevated white blood cell count is not expected Clostridium difficile DNA test results. clen infect dis. Published online February 10, 2021. doi: 10.1093/cid/ciab106