•Nursing education on hemolysis prevention remains an important issue.•We therefore developed videos on ‘best practices’ in hemolysis prevention.•Videos were distributed to clinical nurse educators ...for provision to nurses.•Video distribution was associated with beneficial changes in hemolysis.
Minimizing hemolysis during phlebotomy ensures accurate chemistry results and reduces test cancellations and specimen recollections. We developed videos demonstrating best practices to reduce hemolysis and tested whether distribution to clinical nurse educators (CNEs) for provision to nursing staff affected the degree of specimen hemolysis in hospital inpatient units and outpatient clinics.
Videos of common blood collections demonstrating best practices to reduce hemolysis were filmed and then distributed via email link to all hospital-based CNEs in Calgary, Alberta, Canada. (https://vimeo.com/user18866730/review/159869683/a0cec9827f). Roche Cobas hemolysis index (H-index) results from specimens collected +/- 12 months from the date of video distribution were extracted from Roche Cobas IT middleware (cITM) and linked to collection location. An interrupted time series (ITS) analysis with collection location as the unit of anlaysis was used to quantify impact of video distribution on the trajectory of weekly mean log-H-index weighted by inverse variance.
In +/- 3 months of data flanking video distribution (n = 137 241 collections), where overall impact was strongest, H-index trajectory (change in units per week) decreased immediately following video distribution (-5.7% / week, p < 0.01). This was accompanied by a 22% drop in overall H-index from the week before to the week after video distribution (y-intercept change, or gap). There was also a small but significant overall decrease in the proportion of hemolyzed specimens (-0.3%, p < 0.01). These changes were not observed at all collection locations, and in fact increases occured at some locations.
We developed a novel and convenient educational aid that, when distributed, was associated with beneficial changes in specimen hemolysis at hospital inpatient units and outpatient clinics. Including it in ongoing nursing education will fill a knowledge gap that may help to reduce specimen hemolysis.
Background
The objective of this study was to quantify the sensitivity of very low concentrations of high‐sensitivity cardiac troponin T (hsTnT) at ED arrival for acute myocardial infarction (AMI) in ...a large cohort of chest pain patients evaluated in real‐world clinical practice.
Methods
This retrospective study included consecutive ED patients with suspected cardiac chest pain evaluated in four urban EDs, excluding those with ST‐elevation AMI, cardiac arrest or abnormal kidney function. The primary outcomes were AMI at 7, 30, and 90 days. Secondary outcomes included major adverse cardiac events (MACE; all‐cause mortality, AMI, and revascularization) and the individual MACE components. Test characteristics were calculated for hsTnT values from 3 to 200 ng/L .
Results
A total of 7,130 patients met inclusion criteria. AMI incidences at 7, 30, and 90 days were 5.8, 6.0, and 6.2%. When the hsTnT assay was performed at ED arrival, the limit of blank of the assay (3 ng/L) ruled out 7‐day AMI in 15.5% of patients with 100% sensitivity and negative predictive value (NPV). The limit of detection of the assay (5 ng/L) ruled out AMI in 33.6% of patients with 99.8% sensitivity and 99.95% NPV for 7‐day AMI. The limit of quantification (the Food and Drug Administration FDA‐approved cutoff for lower the reportable limit) of 6 ng/L ruled out AMI in 42.2% of patients with 99.8% sensitivity and 99.95% NPV. The sensitivities of the cutoffs of <3, <5, and <6 ng/L for 7‐day MACE were 99.6, 97.4, and 96.6%, respectively. The NPVs of the cutoffs of <3, <5, and <6 ng/L for 7‐day MACE were 99.8, 99.5, and 99.4%, respectively. A secondary analysis was performed in a subgroup of 3,549 higher‐risk patients who underwent serial troponin testing. In this subgroup, a cutoff of 3 ng/L ruled out 7‐day AMI in 9.6% of patients with 100% sensitivity and NPV, a cutoff of 5 ng/L ruled out 7‐day AMI in 23.3% of patients with 99.7% sensitivity and 99.9% NPV, and a cutoff of 6 ng/L ruled out 7‐day AMI in 29.8% of patients with 99.7 and 99.9% NPV. In the higher‐risk subgroup, the sensitivities of cutoffs of <3, <5, and <6 ng/L for 7‐day MACE were 99.8, 97.4, and 96.6%, respectively. In this higher‐risk subgroup, the NPV of cutoffs of <3, <5, and <6 ng/L for 7‐day MACE were 99.7, 98.5, and 98.4%, respectively.
Conclusions
When used in real‐world clinical practice conditions, hsTnT concentrations < 6 ng/L (below the lower reportable limit for an FDA‐approved assay) at the time of ED arrival can rule out AMI with very high sensitivity and NPV. The sensitivity for MACE is unacceptably low, and thus a single‐troponin rule‐out strategy should only be used in the context of a structured risk evaluation.
Rapid/point-of-care respiratory virus nucleic acid tests (NAT) may improve oseltamivir, antibiotic, diagnostic test, and hospital bed utilization. Previous randomized controlled trials (RCT) on this ...topic have not used standard procedures of an accredited healthcare and laboratory system. We conducted a parallel RCT at two hospitals paediatric = Alberta Children's Hospital (ACH); primarily adult = Peter Lougheed Centre (PLC). Patients with a respiratory viral testing order were randomized to testing at either a central accredited laboratory (standard arm) or with a rapid polymerase chain reaction test at an on-site accredited laboratory followed by standard testing rapid on-site test (ROST) arm based on day of specimen receipt at the laboratory. Patients and clinicians were blinded to assignment. 706 patient encounters were included at ACH; 322 assigned to ROST (181 inpatients) and 384 to the standard arm (194 inpatients). 422 patient encounters were included at PLC; 200 assigned to ROST (157 inpatients) and 222 to the standard arm (175 inpatients). In a RCT representing implementation of ROST in an accredited laboratory system, we found that a ROST improved oseltamivir utilization and is the first RCT to show reduced ancillary testing in both paediatric and adult populations. A larger study is required to assess reduction in paediatric LOS as ACH was underpowered. These findings help justify the implementation of rapid on-site respiratory virus testing for inpatients.
Abstract Background Symptoms of acute coronary syndromes (ACS) account for a large proportion of emergency department (ED) visits and hospitalizations. High-sensitivity troponin can rapidly rule-out ...or rule-in acute myocardial infarction (AMI) within a short time of ED arrival. We sought to validate test characteristics and classification performance of two-hour high-sensitivity troponin T (hsTnT) algorithms for the rapid diagnosis of AMI. Methods We included consecutive patients from four academic EDs with suspected cardiac chest pain who had hsTnT assays performed two hours apart (+/- 30 minutes) as part of routine care. The primary outcome was AMI at 7 days. Secondary outcomes included major adverse cardiac events (MACE: mortality, AMI and revascularization). Test characteristics and classification performance for multiple 2-hour algorithms were quantified. Results 722 patients met inclusion criteria. 7-day AMI incidence was 10.9% and MACE incidence was 13.7%. A two-hour rule-out algorithm proposed by Reichlin and colleagues ruled out AMI in 59.4% of patients with 98.7% sensitivity and 99.8% NPV. The two-hour rule-out algorithm proposed by the UK National Institute for Health and Care Excellence ruled out AMI in 50.3% of patients with similar sensitivity and NPV. Other exploratory algorithms had similar sensitivity but marginally better classification performance. Reichlin et al’s two-hour rule-in algorithm ruled in AMI in 16.5% of patients with 92.4% specificity and 58.5% PPV. Conclusion 2-hour hsTnT algorithms can rule-out AMI with very high sensitivity and NPV. The algorithm developed by Reichlin et al. had superior classification performance. Reichlin and colleagues' 2-hour rule-in algorithm had poor PPV and may not be suitable for early rule-in decision-making.
Ameloblastoma is a rare odontogenic tumor which may be complicated by hypercalcemia in advanced disease. Tumoral parathyroid hormone-related peptide (PTHrP) production and local osteolysis from ...paracrine factors have been proposed as mechanisms. Mitogen-activated protein kinase (MAPK) inhibitors have been successfully used in ameloblastomas with BRAF V600E mutation to reduce symptoms and decrease tumor burden. Serum calcium has been observed to normalize following treatment with MAPK inhibitors; however, the response of PTHrP and markers of bone turnover has not been reported. We describe a case of a 55-year-old female with PTHrP-mediated hypercalcemia secondary to BRAF V600E-positive ameloblastoma with pulmonary metastases. Following treatment with dabrafenib and trametinib, the patient experienced the regression of pulmonary lesions and normalization of serum calcium, PTHrP, and markers of bone turnover. Tissue samples of ameloblastoma carrying BRAF V600E mutation are more likely to express PTHrP than tissue samples carrying wild-type BRAF. In our case, resolution of PTHrP-mediated hypercalcemia following initiation of BRAF/MEK inhibition provides additional evidence that the MAPK pathway contributes to PTHrP synthesis. It also raises the question of whether MAPK inhibitors would be effective in treating PTHrP-mediated hypercalcemia associated with other malignancies harboring BRAF V600E mutation.
In vitro deamination generates ammonia in freshly collected blood specimens. To prevent this, samples for ammonia testing are usually collected on ice and run rapidly (e.g., within 1h). We developed ...a method to stabilize specimens for ammonia analysis.
Following plasma separation, 500μmol/l cycloserine or a combination of 2mmol/l sodium borate with 5mmol/l l-serine were added to sample pools with normal or increased concentrations of ALT and/or GGT to inhibit deamination; and/or residual platelets were removed via centrifugation. Sample pools were then incubated at room temperature or 4°C. Untreated sample pools were also incubated at −80°C. Ammonia was measured at 0, 1, 2, 4, 8, 16, and 24h.
When incubated at 4°C without treatment, sample pools with enzymes within their reference limit had an increase of 0.5μmol/l/h, whereas sample pools with ALT and/or GGT activity above their upper reference limit had an increase of 3.6μmol/l/h (p<0.001). When sample pools were incubated at 4°C with sodium borate/l-serine, the rate of ammonia increase was significantly reduced in samples with normal (0.3μmol/l/h, p<0.001 vs. untreated controls) or high enzyme activity (0.1μmol/l/h, p<0.001 vs. untreated controls). Independent of the ALT and/or GGT concentrations, storing the sample at −80°C also preserved the specimens for ammonia analysis (0.2μmol/l/h, p<0.001 vs. untreated controls).
By combining sodium borate/l-serine with refrigeration, plasma ammonia specimens can be stabilized for >12h.
•We present a simple method to preserve ammonia in clinical specimens.•This method preserves plasma ammonia specimens for >12h.•In vitro ammonia increase is inhibited by 2mmol/L sodium borate+5mmol/L l-serine at 4°C.•This method works for samples with both normal and high levels of ALT/GGT activity.
We compare measurement uncertainty (MU) calculations to real patient result variation observed by physicians using as our model anion gap (AGAP) sequentially measured on two different instrument ...types. An approach for discretely quantifying the pre-analytical contributions and validating AGAP MU estimates for interpretation of patient results is proposed.
AGAP was calculated from sodium, chloride, and bicarbonate reported from chemistry or blood gas analyzers which employ different methodologies and specimen types. AGAP MU was calculated using a top-down approach both assuming no correlation between measurands and alternatively, including consideration of measurand correlation. MU-derived reference change values (RCV) were calculated between chemistry and blood gas analyzers results. Observational paired AGAP data (n=39,626 subjects) was obtained from retrospectively analyzed specimens from five urban tertiary care hospitals in Calgary, Alberta, Canada.
The MU derived AGAP RCV for paired specimen data by the two platforms was 5.2-6.1 mmol/L assuming no correlation and 2.6-3.1 mmol/L assuming correlation. From the paired chemistry and blood gas data, total observed variation on a reported AGAP has a 95% confidence interval of ±6.0 mmol/L. When the MU-derived RCV assuming correlation is directly compared against the observed distribution of patient results, we obtained a pre-analytical variation contribution of 2.9-3.5 mmol/L to the AGAP observed variation. In contrast, assuming no correlation leads to a negligible pre-analytical contribution (<1.0 mmol/L).
MU estimates assuming no correlation are more representative of the total variation seen in real patient data. We present a pragmatic approach for validating an MU calculation to inform clinical decisions and determine the pre-analytical contribution to MU in this system.
A comprehensive set of age- and gender-specific pediatric reference intervals is essential for accurate interpretation of laboratory tests in a pediatric setting.
1459 serum/plasma from children ...attending select outpatient clinics and deemed to be metabolically stable, were collected from five age groups; 0–12 months, 1–5 years, 6–10 years, 11–14 years and 15–20 years. Samples were analyzed for 24 chemistries and 15 immunoassays on ARCHITECT ci8200.
Reference intervals were established according to CLSI/IFCC C28-P3 guidelines by the Robust statistical method. The ranges reflect the central 95% confidence intervals for the population tested. Age and gender were partitioned using the Harris–Boyd method.
While these intervals are ci8200 method specific, they not only provide robust intervals for users of this system but are also useful for any laboratory requiring pediatric intervals if they can be shown to be transferable and if validated for the local patient population.
Adaptation of the Randox Enzymatic Manual UV Ammonia method to be used on the Roche Cobas 6000 (c501) automated analyzer platform.
The Randox ammonia reagent was evaluated for precision, linearity, ...accuracy and interference from hemolysis, icterus and lipemia on the Roche c501 analyzer. Comparison studies were conducted for the Randox reagent between Roche c501, Siemens Vista, Ortho Vitros 250, and Beckman DxC methods.
The Randox reagent demonstrates acceptable within-run (L1=65μmol/L, CV 3.4% L2=168μmol/L, CV 1.9%) and between-run precision (L1=29μmol/L, CV 7.3% L2=102μmol/L, CV 3.0%), Analytical Measurement Range (7–940μmol/L), and accuracy. The method interference profile is superior for the Randox method (hemolysis index up to 600, icteric index up to 60, lipemic index up to 100) as compared to the Roche method (hemolysis index up to 200, icteric index up to 10, lipemic index up to 50). Comparison was very good between the Randox reagent and two other wet chemistry platforms.
The Randox Enzymatic Manual UV Ammonia reagent is an available alternative to the Roche Cobas c501 reagent. The method is more robust to endogenous interferences and less prone to instrument error flags, thus allowing the majority of clinical specimens to be reported without additional sample handling at our institution.
•Roche c501 reagent has a 25% frequency of instrument error flags for ammonia samples.•We describe the evaluation of an enzymatic ammonia reagent produced by Randox Inc.•The reagent was adapted for the Roche Cobas c501 automated instrument platform.•The Randox application required several modifications to perform well on the c501.•The evaluated method has significantly reduced rates of instrument error flags.
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