Educational cost-effective intervention to reduce pathologist's peripheral blood smears reviews with non-contributory findings: an academic institution experience.

Peripheral blood smear (PBS) review by a pathologist is a necessary and invaluable diagnostic tool. However, innovative highly sophisticated haematology analysers that flag peripheral blood abnormalities have decreased the need for a PBS review. Ordering practices including PBS reviews lumped as part of an 'order set' or with complete blood count (CBC) constituted most PBS requests at our institution. A retrospective review of all PBS review orders from 1 April 2016 to 31 January 2017 was performed to investigate the ordering practices at our institution. A total of 2864 PBS were ordered during the above study period. In many cases, the PBS report did not add any significant clinical information beyond that acquired by the CBC and differential count. These findings inspired policy changes within our institution for pathologist PBS reviews. Within the electronic order system, all PBS orders for inpatients were linked to a pop-up window with criteria for peripheral smear review and instructions on the approval policy. Outpatient orders required clinicians to request pathology approval. This implementation reduced total number of PBS orders by 42.5% with no adverse effect on patient management. Empowering pathologists and clinicians with guidelines on PBS review orders is a beneficial educational exercise of resource utilisation. Discussion with physicians regarding clinical indications reduces non-contributory PBS reviews, provides guidance to appropriate testing, and aptly allocates pathologist and laboratory staff time and resources.

Assessment of a portable lactate meter for field use in the white rhinoceros (Ceratotherium simum).

Blood lactate is a predictor of mortality in critically ill humans and animals. Handheld lactate meters have the potential to be used in the field to evaluate the condition of severely injured rhinoceroses but have not been compared with laboratory-based methods. Agreement between a handheld lactate meter and a laboratory method was assessed, as was the stability of rhino blood lactate in the anticoagulant sodium fluoride/potassium oxalate (fluoride/oxalate). Blood samples were obtained from 53 white rhinos that had been immobilised for management reasons. Lactate was measured by means of a handheld meter using whole blood in heparin (WBHEP), whole blood in fluoride/oxalate (WBFO) and fluoride/oxalate plasma (PFO). Results were recorded in both blood (BL) and plasma (PL) modes and compared to an established laboratory method for measuring plasma lactate. To assess the stability of lactate over time, blood lactate in fluoride/oxalate was measured on the handheld meter at intervals for up to 91 h. Agreement was best using WBFO in PL mode, with small bias (-0.16), tight 95% limits of agreement (LOA) (-1.46, 1.14) and a Pc (95% CI) of 0.97 (0.92, 0.99). The agreement was improved for all sample types when using the PL mode compared to the blood lactate (BL) mode. Blood lactate was stable in fluoride/oxalate for 91 h, with a mean change from baseline of 0.15 (-0.178, 0.478) mmol/L (mean, 95% CI). The handheld meter was found to be suitable for field use in white rhinos but provided more reliable results with the device in PL mode. Furthermore, rhino blood lactate was found to be stable in fluoride/oxalate for as long as 3 days.

Hemoglobin-Dilution Method: Effect of Measurement Errors on Vascular Volume Estimation.

The hemoglobin-dilution method (HDM) has been used to estimate changes in vascular volumes in patients because direct measurements with radioisotopes are time-consuming and not practical in many facilities. The HDM requires an assumption of initial blood volume, repeated measurements of plasma hemoglobin concentration, and the calculation of the ratio of hemoglobin measurements. The statistics of these ratio distributions resulting from measurement error are ill-defined even when the errors are normally distributed. This study uses a "Monte Carlo" approach to determine the distribution of these errors. The finding was that these errors could be closely approximated with a log-normal distribution that can be parameterized by a geometric mean (X) and a dispersion factor (S). When the ratio of successive Hb concentrations is used to estimate blood volume, normally distributed hemoglobin measurement errors tend to produce exponentially higher values of X and S as the SD of the measurement error increases. The longer tail of the distribution to the right could produce much greater overestimations than would be expected from the SD values of the measurement error; however, it was found that averaging duplicate and triplicate hemoglobin measurements on a blood sample greatly improved the accuracy.

Assessment of red blood cell deformability in type 2 diabetes mellitus and diabetic retinopathy by dual optical tweezers stretching technique.

A pilot cross sectional study was conducted to investigate the role of red blood cells (RBC) deformability in type 2 diabetes mellitus (T2DM) without and with diabetic retinopathy (DR) using a dual optical tweezers stretching technique. A dual optical tweezers was made by splitting and recombining a single Nd:YAG laser beam. RBCs were trapped directly (i.e., without microbead handles) in the dual optical tweezers where they were observed to adopt a "side-on" orientation. RBC initial and final lengths after stretching were measured by digital video microscopy, and a Deformability index (DI) calculated. Blood from 8 healthy controls, 5 T2DM and 7 DR patients with respective mean age of 52.4 yrs, 51.6 yrs and 52 yrs was analysed. Initial average length of RBCs for control group was 8.45 ± 0.25 µm, 8.68 ± 0.49 µm for DM RBCs and 8.82 ± 0.32 µm for DR RBCs (p < 0.001). The DI for control group was 0.0698 ± 0.0224, and that for DM RBCs was 0.0645 ± 0.03 and 0.0635 ± 0.028 (p < 0.001) for DR group. DI was inversely related to basal length of RBCs (p = .02). DI of RBC from DM and DR patients was significantly lower in comparison with normal healthy controls. A dual optical tweezers method can hence be reliably used to assess RBC deformability.

Use of Six Sigma Worksheets for assessment of internal and external failure costs associated with candidate quality control rules for an ADVIA 120 hematology analyzer.

BACKGROUND: Quality control (QC) validation is an essential tool in total quality management of a veterinary clinical pathology laboratory. Cost-analysis can be a valuable technique to help identify an appropriate QC procedure for the laboratory, although this has never been reported in veterinary medicine. OBJECTIVE: The aim of this study was to determine the applicability of the Six Sigma Quality Cost Worksheets in the evaluation of possible candidate QC rules identified by QC validation. METHODS: Three months of internal QC records were analyzed. EZ Rules 3 software was used to evaluate candidate QC procedures, and the costs associated with the application of different QC rules were calculated using the Six Sigma Quality Cost Worksheets. The costs associated with the current and the candidate QC rules were compared, and the amount of cost savings was calculated. RESULTS: There was a significant saving when the candidate 1-2.5s, n = 3 rule was applied instead of the currently utilized 1-2s, n = 3 rule. The savings were 75% per year (£ 8232.5) based on re-evaluating all of the patient samples in addition to the controls, and 72% per year (£ 822.4) based on re-analyzing only the control materials. The savings were also shown to change accordingly with the number of samples analyzed and with the number of daily QC procedures performed. CONCLUSIONS: These calculations demonstrated the importance of the selection of an appropriate QC procedure, and the usefulness of the Six Sigma Costs Worksheet in determining the most cost-effective rule(s) when several candidate rules are identified by QC validation.

Assessment of accuracy of the structure-factor-size-estimator method in determining red blood cell aggregate size from ultrasound spectral backscatter coefficient.

A computer simulation study to produce ultrasonic backscatter coefficients (BSCs) from red blood cell (RBC) clusters is discussed. The simulation algorithm is suitable for generating non-overlapping, isotropic, and fairly identical RBC clusters. RBCs were stacked following the hexagonal close packing (HCP) structure to form a compact spherical aggregate. Such an aggregate was repeated and placed randomly under non-overlapping condition in the three-dimensional space to mimic an aggregated blood sample. BSCs were computed between 750 KHz and 200 MHz for samples of various cluster sizes at different hematocrits. Magnitudes of BSCs increased with mean aggregate sizes at low frequencies (<20 MHz). The accuracy of the structure-factor-size-estimator (SFSE) method in determining mean aggregate size and packing factor was also examined. A good correlation (R(2) ≥ 0.94) between the mean size of aggregates predicted by the SFSE and true size was found for each hematocrit. This study shows that for spherical aggregates there exists a region for each hematocrit where SFSE works most accurately. Typically, error of SFSE in estimating mean cluster size was <20% for dimensions between 14 and 17 µm at 40% hematocrit. This study suggests that the theoretical framework of SFSE is valid under the assumption of isotropic aggregates.

Age-dependent reference ranges for automated assessment of immature granulocytes and clinical significance in an outpatient setting.

CONTEXT: New generations of hematology analyzers have made the routine automated quantification of immature granulocytes (IGs) in peripheral blood samples accessible as a powerful clinical parameter. OBJECTIVE: The use of IGs has previously been studied mostly in hospitalized patients with sepsis. We investigated the use of IGs in the outpatient setting. Establishment of precise normal outpatient IG reference ranges is a prerequisite for clinically meaningful interpretation of the parameter. DESIGN: We analyzed a large outpatient population comprising more than 2400 samples to determine age-stratified normal reference ranges for IGs. RESULTS: Using nonparametric statistical approaches, we show that 1-tailed 95th percentile estimates for relative and absolute IG concentrations up to the age of 10 years are 0.30% and 30.0 µL(-1), respectively. For individuals above the age of 10 years, the respective 95th percentile estimates are approximately twice as large at 0.74% and 60.0 µL(-1). No differences were seen between male and female reference ranges. Taking nonparametric 90% confidence intervals for each estimate into account, we recommend the following IG upper reference range limits for routine outpatient use: 0.30%/40.0 µL(-1) (≤10 years) and 0.90%/70.0 µL(-1) (>10 years). Up to the age of 10 years, the most common pathologies associated with elevated IG counts in outpatients were infections, in particular, otitis media, upper and lower respiratory infections, and gastroenteritis. By contrast, above the age of 10 years, the most common causes were hematologic malignancies, drug therapy (glucocorticoids, chemotherapy), severe infections, and pregnancy (young females). CONCLUSIONS: The use of appropriate reference ranges makes IGs a powerful hematologic parameter for outpatient care that is associated with differential diagnoses that are distinctly characteristic of that setting.

Molecular epidemiology of a Pseudomonas aeruginosa hospital outbreak driven by a contaminated disinfectant-soap dispenser.

BACKGROUND AND OBJECTIVE: Pseudomonas aeruginosa infection represents a main cause of morbidity and mortality among immunocompromised patients. This study describes a fatal epidemic of P. aeruginosa that occurred in a hematology unit in Italy. METHODS: Retrospective cohort study, prospective surveillance, auditing, extensive testing on healthcare workers and environmental investigation were performed to define the dynamics and potential causes of transmission. RAPD, macrorestriction analyses and sequence typing were used to define relationships between P. aeruginosa isolates. RESULTS: Eighteen cases of infection were identified in the different phases of the investigation. Of these, five constitute a significant molecular cluster of infection. A P. aeruginosa strain with the same genetic fingerprint and sequence type (ST175) as clinical isolates strain was also isolated from a heavily contaminated triclosan soap dispenser. DISCUSSION AND CONCLUSIONS: Our results are consistent with the hypothesis that patients became indirectly infected, e.g., during central venous catheter handling through contaminated items, and that the triclosan soap dispenser acted as a common continuous source of P. aeruginosa infection. Since P. aeruginosa is intrinsically unsusceptible to triclosan, the use of triclosan-based disinfectant formulations should be avoided in those healthcare settings hosting patients at high risk of P. aeruginosa infection.

Technology and laboratory instrumentation in the next decade.

We are affected by many forces as we approach the first decade of the new millennium. Rapid advances in computer technology and robotic automation, from sample identification to collection, processing, analysis, and reporting of results, are opening doors for drastic improvements that will ultimately lead to miniaturization and cost reduction. Noninvasive technology, whether in vivo or ex vivo, is waiting in the wings to make its debut. Technology that has previously had an inordinately long period of gestation, such as near-infrared sensors for noninvasive measurement of glucose and other analytes, could well become a reality. The end of the next decade may be an era of nanotechnology that will drastically change the face of today's clinical laboratory.

Preparing the lab for the year 2001: workstation consolidation.

Laboratories willing to integrate workstation by reorganizing lab space and staffing, advancing ancillary services, and purchasing flexible, high-throughput instrumentation are on the fast track to success as they head toward the 21st century.

Assessment of hypercoagulability in patients with cancer using the Sonoclot Analyzer and thromboelastography.

Patients with cancer have an increased incidence of thrombosis and abnormal haemostasis detectable by sophisticated laboratory tests. Whether abnormalities in such highly sensitive assays is clinically relevant to bleeding or thrombosis is not clear. The thromboelastograph (TEG) and Sonoclot analyzers assess the coagulation process in whole blood and may therefore be physiologically more relevant than assays of isolated haemostatic components. Blood was collected from healthy volunteers and patients with breast cancer, colorectal cancer or benign disease and tested in the TEG and Sonoclot. Results in the cancer group were compared to appropriately sex-matched controls. The TEG parameters R (P < 0.02), angle (P < 0.05) and MA (P < 0.001) were abnormal in colorectal cancer; up to 8/17 (47%) patients being assessed as hypercoagulable. R (P < 0.05), angle (P = 0.05) and MA (P < 0.001) were abnormal in breast cancer; 2/21 (9%) patients having abnormal results. In the Sonoclot Analyzer, 11/17 (64%) patients with colorectal cancer had a significant increase in clot rate (P < 0.001) while 2/17 had a decreased SonACT time (P = 0.05). 4/21 (19%) breast cancer patients had a significant increase in clot rate (P < 0.001) and the SonACT was shortened (P = 0.05). Platelets and fibrinogen levels were generally normal and only one patient had clinical evidence of thrombosis. There were no significant coagulation changes in patients with benign colon or breast disease. In conclusion, hypercoagulability was detected in a high proportion of breast and colorectal cancer patients by both techniques. The clot rates of the TEG and Sonoclot were significantly correlated but the latter was abnormal in a greater proportion of cancer patients.