Applying a direct aPTT ratio (PlatelinLS/ActinFS) permits to identify rapidly and reliably a bleeding-related factor deficiency or a lupus anticoagulant sequential to an isolated prolongation of aPTT in paediatric pre-operative screening.

OBJECTIVES: An isolated prolongation of activated partial thromboplastin time (aPTT) found in paediatric pre-operative screening could be due to bleeding or non-bleeding aetiologies. The aim of our study was to evaluate clinical benefits of an additional ActinFS and/or a mixing aPTT study to identify a bleeding-related factor deficiency (BRFD). METHODS: Over a 4-yr period, isolated prolongation of aPTT with PlatelinLS was detected in 308 paediatric patients and confirmed in 161 cases by a 2nd sample. ActinFS, a mixing study, FVIII, FIX, FXI, FXII and lupus anticoagulant (LA) were performed. Three different aPTT ratios between PlatelinLS and ActinFS were analysed. RESULTS: We found 17 BRFD, 31 FXII deficiencies and 64 positive LA. A prolonged ActinFS had a significant association with BRFD (P < 0.0001) while a corrected mixing study did not. The direct aPTT ratio had a significant relationship with positive LA (P < 0.05), and with BRFD (P < 0.0001). Using this ratio, the sensitivity of BRFD's and LA's detection could be increased, respectively, to 82% from 59% using ActinFS alone, and to 86% from 55% using mixing study. CONCLUSIONS: Applying this direct aPTT ratio allows to quickly and reliably identify both BRFD and LA sequential to an isolated prolongation of aPTT.

Performance and abnormal cell flagging comparisons of three automated blood cell counters: Cell-Dyn Sapphire, DxH-800, and XN-2000.

OBJECTIVES: To compare two hematological analyzers-the DxH-800 (DxH; Beckman-Coulter, Miami, FL) and XN-2000 (XN; Sysmex, Kobe, Japan)-with the Cell-Dyn Sapphire (SAPH; Abbott, Santa Clara, CA). METHODS: We analyzed 4,375 samples. Slide reviews were made in the presence of blast, abnormal lymphocyte, and immature granulocyte (IG) flags or nucleated RBC (NRBC) count. RESULTS: The analyzers exhibited excellent correlations for CBC and neutrophils but displayed a limit correlation for lymphocytes. The XN did not miss circulating blasts (0.5%-95% in microscopy). For NRBCs, the XN demonstrated a sensitivity of 90%; DxH, 74%; and SAPH, 29%. Only the XN demonstrated a correlation with microscopy, permitting a WBC six-part differential until 15% of NRBCs. The XN and DxH gave useful IG counts with a cutoff less than 5% and a WBC level more than 2,500/mm(3). For abnormal lymphocytes detection, only XN demonstrated sensitivity of more than 95%, but its specificity of 54% requires adaptation. CONCLUSION: The XN increases the sensitivity of abnormal cell detection compared with the other counters, permitting a seven-part differential between predefined levels, decreasing the slide review from 20% to 9%.