[Fundamental Evaluation and Clinical Usefulness of Lipoprotein Analysis System with Anion-Exchange Chromatography].

We established a method for measurement of the cholesterol concentrations of high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), intermediate density lipoprotein cholesterol (IDL-C) and very low density lipoprotein cholesterol (VLDL-C) by using high performance liquid chromatography (HPLC) with anion-exchange column. The HPLC method has been covered by insurance in 2013, and HLC-729LPII (LPII) system constructed by this method has come on the market in 2014. We evaluated the fundamental precision data of lipoprotein cholesterol values measured by HLC-729 LPII. The within-day and between-day assay coefficients of variation of lipoprotein cholesterol values were 1.4-10.7 (%CV). The lipoprotein profiles of patients with type 2 diabetes mellitus (T2DM, n = 60) without dialysis therapy were measured by LPII. HDL-C obtained by LPII was highly correlated with that obtained by direct assay. LDL-C obtained by LPII was highly correlated with those obtained by direct assay and calculated by Friedewald's formula. In addition, IDL-C obtained by LPII was negatively correlated with estimated Glomerular Filtration Ratio (eGFR). These results suggest that the new HPLC method can be applied to estimate lipoprotein profile of T2DM patients. Particularly, IDL cholesterol may be useful for the evaluation of impaired lipid metabolism in T2DM patients without dialysis therapy, but it remains to be cleared.

[Security Management in Clinical Laboratory Departments and Facilities: Current Status and Issues].

We conducted a questionnaire survey regarding the current activities for protecting patients' privacy and the security of information systems (IS) related to the clinical laboratory departments of university hospitals, certified training facilities for clinical laboratories, and general hospitals in Yamaguchi Prefecture. The response rate was 47% from 215 medical institutions, including three commercial clinical laboratory centers. The results showed that there were some differences in management activities among facilities with respect to continuing education, the documentation or regulation of operational management for paper records, electronic information, remaining samples, genetic testing, and laboratory information for secondary use. They were suggested to be caused by differences in functions between university and general hospitals, differences in the scale of hospitals, or whether or not hospitals have received accreditation or ISO 15189. Regarding the IS, although the majority of facilities had sufficiently employed the access control to IS, there was some room for improvement in the management of special cases such as VIPs and patients with HIV infection. Furthermore, there were issues regarding the login method for computers shared by multiple staff, the showing of the names of personnel in charge of reports, and the risks associated with direct connections to systems and the Internet and the use of portable media such as USB memory sticks. These results indicated that further efforts are necessary for each facility to continue self-assessment and make improvements.

[Draft proposal to estimate true values of serum potassium in samples from patients with myeloproliferative neoplasma].

The pseudohyperkalemia in thrombocytosis is assumed to be due to potassium released from blood cells during blood clotting as reported previously, but its mechanisms remain to be cleared. Although plasma potassium measurements with blood collection tubes containing heparin are performed in many hospitals to avoid pseudohyperkalemia, the burden on patients may come out with further blood sampling by another heparinized tube. Taken together, we investigated laboratory data possibly involved in pseudohyperkalemia in 184 samples from patients with myeloproliferative neoplasma (MPN), and studied estimation capability for true values of serum potassium, driving a correction formula by means of several laboratory data to explain the difference of measured potassium values (K-difference: serum value minus plasma value). Platelet count and mean corpuscular volume (MCV) were adopted as significant variables correlated to K-difference as a result of multiple regression analysis. A correction formula was driven by multiple regression equation with these two variables as follows: y = 0.0006 x 1+0.0004 x 2-0.177 (r= 0.885; x 1, platelet count; x 2, MPV). The correction formula was considered to be useful for estimating the true value of serum potassium in samples from patients with MPN because the corrected serum potassium value correlated highly with plasma potassium value (r = 0.885). These results propose that true values of serum potassium can be estimated by the correction of measured serum potassium values with platelet count and MCV, suggesting that not only quantitative factors but also qualitative factors may be involved in pseudohyperkalemia.

[Triglyceride (TG) and remnant lipoproteins].

Lowering low-density lipoprotein (LDL) cholesterol (LDL-C) can reduce the risk of cardiovascular disease (CVD) by approximately 30%, and the remaining 70% should be the second front of CVD risk reduction. Such residual risks include high triglyceride (TG) concentrations and low levels of high-density lipoprotein (HDL) cholesterol (HDL-C) in terms of dyslipidemia. TG-rich lipoproteins are heterogenous and composed of a variety of subfractions, all of which are not necessarily relevant to atherosclerosis and CVD risk. However, remnant lipoproteins, TG-rich lipoproteins, are atherogenic and related to CVD risk. Two different methods (RLP-C and RemL-C) have been developed to measure cholesterol levels of remnant lipoproteins. Although there is a difference in affinity to intermediate-density lipoprotein (IDL) between the two methods, they may be better qualified as biomarkers of CVD risk than TG itself. TG measurements play a certain role in the evaluation of CVD risk, but the remnant lipoprotein cholesterol measurement can provide better screening for patients at high CVD risk than TG and may be a useful examination in both quantity and quality.

[Medical safety management in the blood collection center of clinical laboratory].

Safety management is essential for providing patients with medical services. Our hospital, opened at Kashiwa in 1987, has been building up systems and taking a number of steps to reduce the blood collection related problems, including venipuncture-related infection, nerve injury, and vasovagal reflex with syncope in accordance with guidelines for the standard method of venipuncture blood collection. We also have made efforts for improving medical services, including reductions in patient waiting time and prevention of patient misidentification, medical test malpractice, and patient privacy. However, ultimately, it is of obvious significance to educate and train communication skills for humanity and friendly kindness because most of medical accidents are basically attributed to communication errors between patients and medical staff.

Serum soluble interleukin-2 receptor in eosinophilia.

The relationship between soluble interleukin-2 receptor (sIL-2R) levels and clinical characteristics was evaluated in patients with eosinophilia. Thirty-eight out of 60 patients showed sIL-2R levels of more than 800 U/ml. In these patients, sIL-2R was closely related to the eosinophil count, but not the IgE level. Their underlying diseases were heterogeneous, including neoplasms and collagen diseases. In patients with lower sIL-2R levels, there was no relationship to the eosinophil count, but sIL-2R was correlated with the IgE level. These findings indicate that patients with eosinophilia and higher sIL-2R levels tend to have underlying diseases other than allergy, and might be more severely ill than patients with lower sIL-2R levels. sIL-2R may be a good marker for evaluating patients with eosinophilia, as an indicator of the probable etiology and severity of their diseases.