International journal of laboratory hematology最新文献

Introduction: There are important challenges with the measurement and interpretation of direct oral anticoagulant (DOAC) anticoagulant effect including a lack of therapeutic ranges, inaccuracy of routinely available coagulation assays, lack of established thresholds for clinically significant effect, and uncertainty about how to apply the results to patient care.

Objective: In this narrative review, we provide a practical approach to DOAC measurement in clinical practice.

Methods: By summarizing the literature and using illustrative cases, we highlight key principles of commonly available tests, outline potential indications for measuring DOAC drug levels, and provide guidance on interpreting results to inform management decisions.

Conclusion: While DOACs do not require routine monitoring of anticoagulant effect, assessment of plasma DOAC concentration may be helpful in select emergency and non-emergency clinical scenarios.

Background: Over the past 40 years, molecular diagnostic methods have evolved from multi-step, time-consuming protocols towards either rapid targeted tests or expansive, massively parallel testing.

Aims: Here we consider the speed limits of targeted molecular diagnostics, considering the three sequential required steps: nucleic acid preparation, amplification, and analysis.

Materials & methods: Instead of the bind/wash/elute steps commonly used for nucleic acid extraction, simple alkaline lysis of whole blood results in a suspension ready for PCR in seconds that can be added directly to an appropriately buffered PCR master mix. For amplification, the time requirements of PCR are typically limited by the temperature cycling instrumentation and not by biochemistry.

Results & discussion: By lowering sample volumes, increasing the surface area to volume ratio, decreasing the thickness of the sample container, decreasing the amplicon size, and inducing rapid temperature changes by a myriad of innovative means, 30 cycles of PCR can easily be completed in less than 5 min. By increasing primer and polymerase concentrations in synchrony with even faster cycling (< 2 s cycles), "extreme PCR" has amplified a 60 bp human genomic target in < 15 s (35 cycles) with high yield and specificity. For analysis, cumbersome, contamination-prone gel analysis can be replaced by melting curve analysis. Although melting curve analysis usually takes up to an hour on commercial instrumentation, precise temperature control can enable single base genotyping in 1-4 s.

Conclusion: These advances demonstrate the feasibility of sample-to-answer molecular diagnostics in seconds.

Introduction: The PNH working group was created in 2010 to initiate a workshop on testing white blood cells to share international recommendations.

Methods: Thirty-five French and Belgian laboratories equipped with 2- or 3-laser cytometers applied three different panels with or without FLAER reagent in 305 samples. This multicenter study demonstrated the interplatform applicability of setting harmonization and the benefits of using a harmonized gating method. A 10^-4 limit of detection was achieved with harmonized multiparametric approaches in both six-color combinations, as well as a robust quantification of minor PNH clones.

Results: Following this workshop, the group has developed a quality control scheme since 2013 to improve PNH diagnosis practices. This annual program includes two surveys, a virtual one and one based on fresh whole-blood sample analysis. Over the last 10 years, the regular participation of the French-speaking registered centers has demonstrated their strong commitment to our program, which offers various PNH clinical situations. Alongside, the conformity of the final reports provided by the participants has increased to 96%.

Conclusion: In 2016, our PNH working group initiated a nationwide multicenter prospective observational study, collecting all PNH cases or GPI-deficient cells above 0.01% to monitor the long-term evolution of minor PNH clones < 1% and to further investigate the relevance of classifying type II and type III PNH cells in WBCs in clones > 1%. The strong network of cytometrists built led us to create in 2018 the French-speaking flow cytometry association in Hematology, namely CytHem, to harmonize the diagnostic practices in various hematological diseases.