Expert consensus regarding standardization of sample preparation for clotting time assays.

Accurate clotting time assay results are vital, as the test is employed to indicate the amount of oral anticoagulant to be prescribed, while it is also used for screening the hemorrhagic and thrombotic diseases. The procedure chosen for preparation of a patient blood sample including centrifugation can contribute to significant differences in the results obtained. Thus, for the purpose of proposing a standardized method to appropriately prepare blood samples prior to assay, the Japanese Society of Laboratory Hematology organized the Working Group for Standardization of Sample Preparation for Clotting Time Assays (WG). Following reviews of previously announced guidelines and original experimental results, consensus was obtained by the WG, with the main findings as follows. (1) The recommended anticoagulant in the blood collection tube is sodium citrate solution at 0.105-0.109 M (3.13-3.2%). (2) Whole blood samples should be stored at room temperature (18-25 ˚C) within 1 h of collection from the patient. (3) For plasma preparation, centrifugation at 1500 × g should be performed for at least 15 min or at 2000 × g for at least 10 min at room temperature. (4) After the plasma sample is prepared, it should be stored at room temperature and assayed within 4 h.

[Measures to prevent patient identification errors in blood collection/physiological function testing utilizing a laboratory information system].

We constructed an integrated personal identification workflow chart using both bar code reading and an all in-one laboratory information system. The information system not only handles test data but also the information needed for patient guidance in the laboratory department. The reception terminals at the entrance, displays for patient guidance and patient identification tools at blood-sampling booths are all controlled by the information system. The number of patient identification errors was greatly reduced by the system. However, identification errors have not been abolished in the ultrasound department. After re-evaluation of the patient identification process in this department, we recognized that the major reason for the errors came from excessive identification workflow. Ordinarily, an ultrasound test requires patient identification 3 times, because 3 different systems are required during the entire test process, i.e. ultrasound modality system, laboratory information system and a system for producing reports. We are trying to connect the 3 different systems to develop a one-time identification workflow, but it is not a simple task and has not been completed yet. Utilization of the laboratory information system is effective, but is not yet perfect for patient identification. The most fundamental procedure for patient identification is to ask a person's name even today. Everyday checks in the ordinary workflow and everyone's participation in safety-management activity are important for the prevention of patient identification errors.

[Comparison of portable apnea monitors in the detection of apnea episode during daytime rest].

Although polysomnography (PSG) is the golden standard for the diagnosis of sleep apnea syndrome (SAS), access to this procedure is limited because it requires special institution and trained technicians. Therefore, many portable recording devices have been developed for detection of SAS including home monitoring. The present study evaluated the usefulness of four portable devices in detecting apneic events. The four devices are, (1) FM-500 thermister sensor type III device, (2) LS-300 pressure sensor type III device, (3) Morpheus pressure sensor type III device, and (4) SD-101, a sheet-type type IV device that detects chest wall movement. This study included 1,114 patients who underwent a daytime rest session during a routine clinic visit. The subjects were asked to remain quiet and in a supine position in a dark room. We compared the respiratory disturbance index (RDI) and number of oxygen desaturation events (OD) measured by the four portable devices in each patient. The RDI and number of OD measured by the device using the thermister sensor were significantly lower than those measured by the three other devices. These findings suggest that when using a portable recording device to screen for SAS, the characteristics of the device should be taken into account.

[Utilization of panic values in our institution: hematological testing].

A panic value is defined as an abnormal value indicating a life-threatening situation. Hematological examination results are sensitive to changes in treatment, and are likely to be influenced by blood collection techniques. Panic values may directly influence the diagnosis in many cases because they are treated as clinical evidence. Therefore, the reported results should be carefully evaluated considering the pathologic condition of the patient. In our institution, panic values are determined based on the following concept: "Panic values are established to determine when to ask the opinion of the physician in charge of the patient regarding the validity or confirmation of the clinical condition when an abnormal value is observed." This report describes our approaches for the utilization of panic values and associated problems. Values were determined by referring to those reported previously in the literature and considering differences between the former panic values and clinical conditions and the prescription history of the patients. The reports were made to the doctors in charge in each of the departments directly by telephone or pager. Clinical technologists obtained clinical information, such as on the diagnosis, infusion solutions, and medications, and asked for approval to conduct additional examinations accordingly. The numbers of reports on each item for six months from March to August in 2008 were summed. As the results, a total of four items (SFMC + TAT + D-d + FDP) accounted for 28%, hemoglobin 15%, platelets 10%, INR 9%, APTT 8%, two or more items of CBC 8%, PT+APTT 7%, differential WBC 6%, CBC + differential WBC 5%, WBC 3%, fibrinogen 0.9%, and AT 0.1%. The number of reports as a percentage of the total orders was 0.14% for CBC-related and 0.49% for hemostasis-related items. Regarding diseases and clinical conditions, blood collection-related events accounted for 11.9%, poor management of warfarin administration 9.3%, leukemia and malignant lymphoma 7.7% and chemotherapy 7.4%, and then under-administration of heparin, DIC, the perinatal period, gastrointestinal hemorrhage, severe hepatic disorder, EBV, and acute virus infection, in order of decreasing frequency. This method enabled the quick and accurate reporting of panic values to clinical sites. Furthermore, clinical technologists could be motivated to increase their awareness of the value of examinations, medications, and treatments and to be more involved in medical practice. However, there were some problems, such as intervening in the clinical practice of physicians in charge, individual variations in the performance level of clinical technologists, and insufficient uniformity of management and calculation of panic values. The provision of clinically useful information will be made possible by constructing systems to send panic values to the mobile terminals of physicians in charge and being able to refer to the results and manage medical records on the system when electronic medical charts begin to be used next year.

A rapid and quantitative D-Dimer assay in whole blood and plasma on the point-of-care PATHFAST analyzer.

The objective of this study was to evaluate the accuracy indices of the new rapid and quantitative PATHFAST D-Dimer assay in patients with clinically suspected deep-vein thrombosis (DVT). Eighty two consecutive patients (34% DVT, 66% non-DVT) with suspected DVT of a lower limb were tested with the D-Dimer assay with a PATHFAST analyzer. The diagnostic value of the PATHFAST D-Dimer assay (which is based on the principle of a chemiluminescent enzyme immunoassay) for DVT was evaluated with pre-test clinical probability, compression ultrasonography (CUS). Furthermore, each patient underwent contrast venography and computed tomography, if necessary. The sensitivity and specificity of the D-Dimer assay using 0.570 mug/mL FEU as a clinical cut-off value was found to be 100% and 63.2%, respectively, for the diagnosis of DVT, with a positive predictive value (PPV) and negative predictive value (NPV) of 66.7% and 100%, respectively. The correlation between the results of PATHFAST D-Dimer and VIDAS D-Dimer was acceptable (y=1.134x+0.003, r=0.902). The test reproducibility was good (CV%: from 4.0% to 5.0% for plasma and from 7.1% to 7.5% for whole blood) and the total imprecision was very good (CV%: 3.6-5.7%). Whole blood as well as plasma can be used as samples in this assay (y=1.013x-0.010, r=0.971 for heparinized specimens; y=1.068x+0.003, r=0.989 for citrated specimens). Because of its high sensitivity and NPV PATHFAST D-Dimer assay can be useful for the rapid rule out of DVT in patients admitted with suspected thrombosis.