[Decrease in number of venipuncture tubes enables us to shorten turnaround times of blood-based testing in clinical laboratories].

We are making efforts to reduce the number of venipuncture tubes for blood-based testing. On the reconstruction of hematology system in 2011, we planned the system to include hemoglobin A1c (HbA1c) assay and to replace the assay instrument for erythrocyte sedimentation rate (ESR) to use EDTA-2K based whole blood. Accordingly, the revised system required a single test tube for hematological testing, resulting in reduction of blood volume collected. It was estimated that the whole blood collected from outpatients in a year decreased from 143 L to 109 L. Also, the times required to complete venipuncture after outpatient accession were significantly shortened to 10(0.71 +/- 0.27) (2.75-9.55) min, and nearly 50% of outpatients experienced < 2 min of waiting. As the times required for venipuncture were shortened, the turnaround times (TATs) from outpatient accession to finally reporting the test results to physicians were also shortened in the blood-based laboratories. The TATs after outpatient accession to reporting the test results in biochemistry and serology ranged 59 to 80 min (90%-tile), indicating 8 to 16 min less when compared with those before system reconstruction. In conclusion, the decrease in number of venipuncture tubes in hematological testing enables us to reduce the blood volume collected, and to shorten (1) times required for venipuncture procedure, (2) waiting times, and (3) TATs for blood-based testing. However, as demonstrated in HbA1c, i.e., a 50%-tile of TAT for HbA1c delayed for 5 min, the configuration of assay system can greatly influence the TATs of individual test parameters.

[Evaluation of turnaround time (TAT) for outpatients from venipuncture accession to reporting test results of blood chemistry and blood cell analysis to physicians].

In response to the revision of social medical insurance policy, in which hospital clinics can additionally charge for laboratory testing when the test results are presented to an outpatient in a print-out form on a visiting day, we evaluated laboratory-spending times, so-called turnaround times (TATs). A total of 14,802 outpatients during the period from October 2010 to May 2011 were enrolled. TATs from venipuncture accession to completing blood collection revealed a log-normal distribution with 5 to 6 min of mode and 10(0.95 +/- 0.26) (4.90 to 16.2) min of mean +/- standard deviation. Order waiting time figured a half-normal distribution, 50% tile and 90%-tile being 4 and 16 min, respectively. TATs of blood collection and order waiting time were significantly influenced by days of the week and accession time. Through analysis of TATs from specimen receipt to reporting test results, it became apparent that the tests determined by immunoassay and erythrocyte sedimentation rate (ESR) required more minutes when compared to the remaining tests. Total TATs from venipuncture accession to reporting test results ranged 28 to 29 min (50%-tile) for complete blood count and hemoglobin A1c, whereas those of endocrinology and tumor markers were 65 to 73 min. In conclusion, the tests determined by immunoassay are rate-limiting for rapid reporting efforts in clinical laboratories. Secondly, TATs of blood collection are mostly influenced by order waiting time depending on days of the week and accession time. At present, there is no target value for TATs, however it is important to recognize the necessity to shorten laboratory-spending TATs.

[Quantitative estimation of preanalytical variables which may influence the determinations of prothrombin time (PT) and activated partial thromboplastin time (APTT)].

Prothrombin time (PT) and activated partial thromboplastin time (APTT) tests principally measure the time for a fibrin clot developed in citrated plasma after activation. For the complexity of chemical reactions, a number of preanalytical variables potentially influence the outcome of results. In the present study, we evaluated some preanalytical variables frequently encountered in clinical settings. The volumes of citrated whole-blood specimens collected from inpatients widely varied from 0.99 ml to 2.90 ml indicating 1.6% of unacceptable rate, whereas none of the specimens from outpatients was out of acceptable range. The citrated whole-blood volume significantly affected the determinations of both PT and APTT; the results indicating the more volume the longer clotting time. Also, whole-blood specimens collected in EDTA2K revealed significantly prolonged PT and APTT values in healthy subjects and the patients with anticoagulant therapy of heparin and of warfarin. Storage conditions, time and temperature might influence the PT and APTT values. In particular, citrated whole-blood specimens stood at room temperature revealed the prolonged clotting time in APTT assay by hours. The effects of other variables evaluated such as a half-volume adjustment, needle gauge or syringe type were negligible. With these results, it was concluded that; first, an accurate venipuncture is critical, particularly venipuncture from patients in wards where many different physicians and nurses are in charge and in changing by days. Secondly, the citrated whole-blood specimens should be assayed quickly without any unnecessary storage at room temperature beyond four hours.

[Identification and characterization of Panton-Valentine leukocidin-positive Staphylococcus aureus isolated in Okinawa, Japan].

We experienced hospital-acquired infection in March 2008 that three nurses became infected with Panton-Valentine leukocidin (PVL)-positive methicillin-resistant Staphylococcus aureus (MRSA). Accordingly, we performed the retrospective study to determine the prevalence of PVL-positive S. aureus in Okinawa. A total of 731 clinical isolates, consisting of 600 MRSA and 131 methicillin-susceptible isolates in Okinawa, were included. Of the isolates, 16 were positive for PVL gene (lukS-PV-lukF-PV). All the PVL-positive isolates were MRSA, and the first appeared in March 2008. The isolates from the University Hospital were characterized as staphylococcal chromosomal cassette mec type IVa. Through the analysis of pulsed-field gel electrophoresis (PFGE), 16 PVL-positive MRSA isolates were divided in three groups. One isolate (the first group) from the other hospital was less similar (< 40% similarity) when compared with the remaining 15 isolates from the University Hospital. The second group consisted of two respective paired isolates from the same department wards, and those were very similar with each other, indicating possible patient-to-patient transmission. The 11 isolates were characterized as the third group with >80% similarity. The DiversiLab system (bioMérieux) based on repetitive-sequence-based PCR typing demonstrated that the isolates of the third group were similar and indistinguishable with the strains of USA300 clone. However, the first and second groups were not determinable which USA clone was the origin. With these, we could conclude that the PVL-positive MRSA close to USA300 clone first appeared in Okinawa in 2008 and is now becoming prevalent multi-focally. Also, person-to-person transmission is already likely in a hospital setting.

[Laboratory-based evaluation of loop-mediated isothermal amplification (LAMP) to detect Cryptosporidium oocyst and Giardia lamblia cyst in stool specimens].

To establish an alternative and more sensitive test method to detect oocyst of Cryptosporidium parvum and cyst of Giardia lamblia in clinical stool specimens, loop-mediated isothermal amplification (LAMP) was evaluated. Minimum cell concentrations at which LAMP assay could detect C. parvum oocyst and G. lamblia cyst were determined as 6.25 x 10(-1) and 3.12 x 10(-1) cells/assay when the stool specimens were spiked with the respective parasites. The results indicated 400 times higher sensitivities or more when compared to the microscopic readings. Twenty and nineteen diarrhea stool specimens spiked with C. parvum oocyst or G. lamblia cyst were assayed by LAMP. The results indicated that 14 (70%) and 16 (84%) samples successfully resulted in positive readings. But the remaining 6 and 3 samples were read as negative probably due to residual stool color. However, further dilutions of DNA extraction samples and addition of bovine serum albumin to LAMP reaction mixture showed positive effects on the occurrence of false-negative readings. With these results, we can conclude that the LAMP assay provides us an accurate and highly sensitive test method to detect C. parvum oocyst and cyst of G. lamblia, in place of labor-intensive and experience-dependent microscopic examination, in clinical laboratories.