ABSTRACT
BACKGROUND: Autoanalyzer ADVIA2120 uses intracellular peroxidase concentration to perform white blood cell (WBC) differential. Therefore, in specimens containing neutrophils with low peroxidase concentration, neutrophils can be miscounted as monocytes or large unstained cells resulting in pseudoneutropenia. Myeloperoxidase deficiency can be detected by the mean peroxidase index (MPXI). The aims of this study are to establish the reference interval of MPXI and define a cut off value for manual slide review to discriminate pseudoneutropenia. METHODS: We calculated reference intervals as mean+/-2SD according to the indirect method of CLSI C28-A3 guideline from MPXI data of 5,802 individuals who took routine health checkup from April 2010 to June 2012. We performed manual slide review on specimens with low MPXI and compared neutrophil differential count of manual method with that of autoanalyzer. When neutrophil differential in manual slide review was >20%P higher than autoanalyzer result, it was regarded as a pseudoneutropenia. We performed ROC analysis using the MPXI results of samples with and without pseudoneutropenia to define a cutoff to discriminate pseudoneutropenia. RESULTS: The reference intervals of MPXI in total population, male, and female were -4.9 to 7.5, -5.5 to 7.3, and -4.5 to 7.5, respectively. The mean value of MPXI was significantly higher in female than in male and there was no difference by age. Twenty-two pseudoneutropenia samples from 7 patients were identified. ROC analysis yielded cutoff value of -20.7 with 94.9% of sensitivity and 77.3% of specificity. CONCLUSIONS: MPXI may be used in the manual slide review guideline for detecting pseudoneutropenia.
Subject(s)
Female , Humans , Male , Discrimination, Psychological , Leukocytes , Metabolism, Inborn Errors , Monocytes , Neutrophils , Peroxidase , ROC CurveABSTRACT
BACKGROUND: Myeloperoxidase (MPO) activity is reduced in iron depletion. MPXI (mean peroxi-dase index) can replace MPO activity as a hematologic parameter in laboratory medicine. We tried to discuss MPXI in iron deficiency anemia (IDA) that was performed with the hematology autoana-lyzer H*2. METHODS: We studied 58 cases of normal control and 53 cases of IDA that showed the complete absence of iron storage in bone marrow. These cases included 17 cases (group I) which did not have any inflammation, or neoplasm and did not use drugs. There were 36 cases (group II) with inflammation, neoplasm and used drug. We also investigated the hematologic parameters and MPXI in 7 cases among 53 previous cases of IDA for follow- up study after iron replacement. The correlations among hematologic, iron parameters and MPXI were investigated in group I and group II. RESULTS: Group I MPXI (-7.7 +/- 3.4) and group II MPXI (-6.4 +/- 3.6) were statistically lower than the normal control MPXI (1.3 +/- 3.6) (P<0.001). Group I MPXI was correlated with Hb, MCV, MCH, MCHC, HDW, serum iron, transferrin saturation rate and serum ferritin (P<0.05) but was not correlat-ed with age, RDW, WBC, platelet count and transferrin binding capacity. Group II MPXI was not correlated with other hematologic or iron parameters. The normal control MPXI was not correlated with other normal controls, hematologic or iron parameters. After iron replacement, the MPXI, hemoglobin and RBC indices tended to increase and HDW tended to decrease in the follow-up IDA. CONCLUSIONS: MPXI reduced in iron deficiency anemia and appeared to be affected by various state of the patients. MPXI increased after iron replacement, which suggested that MPO activity was restored.
Subject(s)
Humans , Anemia, Iron-Deficiency , Bone Marrow , Ferritins , Follow-Up Studies , Hematology , Inflammation , Iron , Peroxidase , Platelet Count , TransferrinABSTRACT
Myeloperoxidase (MPO) deficiency is rare and its symptoms are not specific; and therefore, it is not easy to identify persons either totally or partially who are myeloperoxidase deficient with every routine analysis. MPO deficiency can be detected by the pattern of the cytogram and the mean peroxidase index (MPXI) using the automated hematology analyzer Technicon H*2. A case of MPO deficiency is reported with some review of the available literatures.