title: Procalcitonin-reduced sensitivity and specificity in heavily leucopenic and immunosuppressed patients.
abstract: Procalcitonin (PCT) has proven to be a very sensitive marker of sepsis for non-leucopenic patients. Little is known about its relevance in immunosuppressed and leucopenic adults. Four hundred and seventy-five PCT determinations were carried out in 73 haematological patients: on 221 occasions the white blood cell (WBC) count was < 1.0 x 10(9)/l and on 239 occasions it was > 1.0 x 10(9)/l leucocytes. Patients were classified as: non-systemic infected controls (n = 280), patients with bacteraemia (n = 32), sepsis (n = 30), severe sepsis (n = 3), septic shock (n = 3) and systemic inflammatory response syndrome (SIRS) (n = 62). When the WBC count was > 1.0 x 10(9)/l, gram-negative bacteria induced higher PCT levels (median 9.4 ng/ml) than gram-positives (median 1.4 ng/ml). In cases with a WBC < 1.0 x 10(9)/l, PCT levels were similar for gram-negative and gram-positive bacteria (1.1 ng/ml versus 0.85 ng/ml). Regardless of the leucocyte count, the median PCT level in bacteraemia cases always remained < 0.5 ng/ml. In heavily leucopenic situations, PCT levels were never > 2 ng/ml even in the sepsis and severe sepsis/septic shock groups, whereas a WBC count > 1.0 x 10(9)/l resulted in median PCT values of 4.1 ng/ml and 45 ng/ml respectively. The positive predictive value for sepsis (cut-off 2 ng/ml) was 93% in cases of WBC count > 1.0 x 10(9)/l, but only 66% in leucopenic conditions. The negative predictive value (cut-off 0.5 ng/ml) was 90% when the WBC count was > 1.0 x 10(9)/l and 63% in leucopenic conditions. Procalcitonin is an excellent sepsis marker with a high positive- and negative-predictive value in patients with WBC count > 1.0 x 10(9)/l, but it does not work satisfactorily below this leucocyte count.
authors.affiliation: Department of Haematology Regional Hospital Bozen, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Svaldi
authors.forename: J
authors.initials: J
authors.lastname: Hirber
authors.forename: A I
authors.initials: AI
authors.lastname: Lanthaler
authors.forename: O
authors.initials: O
authors.lastname: Mayr
authors.forename: S
authors.initials: S
authors.lastname: Faes
authors.forename: E
authors.initials: E
authors.lastname: Peer
authors.forename: M
authors.initials: M
authors.lastname: Mitterer
mesh_terms: D001424:Bacterial Infections / Q000150:complications / Q000175:diagnosis* / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D006801:Humans; D007165:Immunosuppression Therapy; D007958:Leukocyte Count; D007970:Leukopenia / Q000097:blood* / Q000382:microbiology*; D011237:Predictive Value of Tests; D011498:Protein Precursors / Q000097:blood*; D018805:Sepsis / Q000175:diagnosis; D012772:Shock, Septic / Q000175:diagnosis; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide