Mapping point-of-care performance using locally-smoothed median and maximum absolute difference curves

2011 ◽  
Vol 49 (10) ◽  
Author(s):  
Gerald J. Kost ◽  
Nam K. Tran ◽  
Harpreet Singh
Keyword(s):  
Point Of Care ◽  
Absolute Difference ◽  
Maximum Absolute Difference ◽  
Mapping Point ◽  
Care Performance

Validation of a hand-held point of care device for lactate in adult and pediatric patients using traditional and locally-smoothed median and maximum absolute difference curves

2017 ◽  
Vol 468 ◽  
pp. 145-149 ◽  
Author(s):  
Jessica Marie Colon-Franco ◽  
Stanley F. Lo ◽  
Sergey S. Tarima ◽  
David Gourlay ◽  
Amy L. Drendel ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Point Of Care ◽  
Absolute Difference ◽  
Maximum Absolute Difference

Usefulness of point-of-care ultrasound in military medical emergencies performed by young military medicine residents

2019 ◽  
pp. jramc-2018-001132
Author(s):  
Pierre Perrier ◽  
J Leyral ◽  
O Thabouillot ◽  
D Papeix ◽  
G Comat ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Clinical Examination ◽  
Point Of Care ◽  
Military Medicine ◽  
Final Diagnosis ◽  
Absolute Difference ◽  
Point Of Care Ultrasound ◽  
Medical Emergencies ◽  
The Mean ◽  
A Prospective Study

IntroductionTo evaluate the usefulness of point-of-care ultrasound (POCUS) performed by young military medicine residents after short training in the diagnosis of medical emergencies.MethodsA prospective study was performed in the emergency department of a French army teaching hospital. Two young military medicine residents received ultrasound training focused on gall bladder, kidneys and lower limb veins. After clinical examination, they assigned a ‘clinicaldiagnostic probability’ (CP) on a visual analogue scale from 0 (definitely not diagnosis) to 10 (definitive diagnosis). The same student performed ultrasound examination and assigned an ‘ultrasounddiagnostic probability’ (UP) in the same way. The absolute difference between CP and UP was calculated. This result corresponded to the Ultrasound Diagnostic Index (UDI), which was positive if UP was closer to the final diagnosis than CP (POCUS improved the diagnostic accuracy), and negative conversely (POCUS decreased the diagnostic accuracy).ResultsForty-eight patients were included and 48 ultrasound examinations were performed. The present pathologies were found in 14 patients (29%). The mean UDI value was +3 (0–5). UDI was positive in 35 exams (73%), zero in 12 exams (25%) and negative in only one exam (2%).ConclusionPOCUS performed after clinical examination increases the diagnostic accuracy of young military medicine residents.

scholarly journals Evaluation of point-of-care glucose testing accuracy using locally-smoothed median absolute difference curves

2008 ◽  
Vol 389 (1-2) ◽  
pp. 31-39 ◽  
Author(s):  
Gerald J. Kost ◽  
Nam K. Tran ◽  
Victor J. Abad ◽  
Richard F. Louie
Keyword(s):  
Point Of Care ◽  
Absolute Difference ◽  
Glucose Testing ◽  
Testing Accuracy ◽  
Median Absolute Difference

scholarly journals AnemoCheck-LRS: an optimized, color-based point-of-care test to identify severe anemia in limited-resource settings

BMC Medicine ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Marina S. Perez-Plazola ◽  
Erika A. Tyburski ◽  
Luke R. Smart ◽  
Thad A. Howard ◽  
Amanda Pfeiffer ◽  
...  
Keyword(s):  
Screening Tool ◽  
Point Of Care ◽  
Low Cost ◽  
Limited Resource ◽  
Absolute Difference ◽  
Severe Anemia ◽  
Detection Range ◽  
Point Of Care Test ◽  
Colour Scale ◽  
Life Saving

Abstract Background Severe anemia is common and frequently fatal for hospitalized patients in limited-resource settings. Lack of access to low-cost, accurate, and rapid diagnosis of anemia impedes the delivery of life-saving care and appropriate use of the limited blood supply. The WHO Haemoglobin Colour Scale (HCS) is a simple low-cost test but frequently inaccurate. AnemoCheck-LRS (limited-resource settings) is a rapid, inexpensive, color-based point-of-care (POC) test optimized to diagnose severe anemia. Methods Deidentified whole blood samples were diluted with plasma to create variable hemoglobin (Hb) concentrations, with most in the severe (≤ 7 g/dL) or profound (≤ 5 g/dL) anemia range. Each sample was tested with AnemoCheck-LRS and WHO HCS independently by three readers and compared to Hb measured by an electronic POC test (HemoCue 201+) and commercial hematology analyzer. Results For 570 evaluations within the limits of detection of AnemoCheck-LRS (Hb ≤ 8 g/dL), the average difference between AnemoCheck-LRS and measured Hb was 0.5 ± 0.4 g/dL. In contrast, the WHO HCS overestimated Hb with an absolute difference of 4.9 ± 1.3 g/dL for samples within its detection range (Hb 4–14 g/dL, n = 405). AnemoCheck-LRS was much more sensitive (92%) for the diagnosis of profound anemia than WHO HCS (22%). Conclusions AnemoCheck-LRS is a rapid, inexpensive, and accurate POC test for anemia. AnemoCheck-LRS is more accurate than WHO HCS for detection of low Hb levels, severe anemia that may require blood transfusion. AnemoCheck-LRS should be tested prospectively in limited-resource settings where severe anemia is common, to determine its utility as a screening tool to identify patients who may require transfusion.

Point-of-care genetic profiling and/or platelet function testing in acute coronary syndrome

2016 ◽  
Vol 115 (02) ◽  
pp. 382-391 ◽  
Author(s):  
Jean-Philippe Collet ◽  
Mathieu Kerneis ◽  
Jean-Sebastien Hulot ◽  
Stephen A. O’Connor ◽  
Johanne Silvain ◽  
...  
Keyword(s):  
Acute Coronary Syndrome ◽  
Platelet Function ◽  
Platelet Reactivity ◽  
Point Of Care ◽  
Absolute Difference ◽  
Function Measurement ◽  
Genetic Profiling ◽  
Coronary Syndrome ◽  
Bedside Test ◽  
Function Testing

SummaryOur aim was to demonstrate that the sequential use of the Verigene® rapid CYP2C19 test for genetic profiling and the VerifyNowTM bedside test for platelet function measurement in ACS patients may optimise P2Y12 inhibition. “Rapid” (CYP2C19*1/*1 or CYP2C19*17 carriers, n=211) and “slow” metabolisers (CYP2C19*2 carriers, n=58) were first put on clopidogrel and prasugrel for ≥ 2 weeks, respectively. Patients with low platelet reactivity (PRU< 30) on prasugrel or high platelet reactivity (> 208 PRU) on clopidogrel were then switched to clopidogrel and prasugrel, respectively. Our objectives were (i) to demonstrate that the proportion of “rapid” metabolisers on 75 mg of clopidogrel within 30–208 (PRU) of P2Y12 inhibition is non-inferior to “slow” metabolisers on prasugrel 10 mg and (ii) to evaluate the same end-point after switching drugs. The proportion of “rapid” and “slow” metabolisers within 30–208 PRU of P2Y12 inhibition was 71 % and 56.9 %, respectively, an absolute difference of +14.1 % (95 % CI, –0.05 % to 28.28 %) with a non-inferiority margin greater than the predefined margin of –10 %. Among patients out of target, all but one “slow” metabolisers displayed low-on prasugrel platelet reactivity while the majority of “rapid” metabolisers (68 %) displayed high-on clopidogrel platelet reactivity. After switching, the proportion of patients within 30–208 PRU of P2Y12 inhibition was 83.6 % and 79.3 % in “rapid” and “slow” metabolisers, respectively (+4.3 %, 95 % CI –7.3 % to 15.9 %). In conclusion, this study demonstrates a loose relationship between genotype and platelet function phenotype approaches but that they are complementary to select prasugrel or clopidogrel MD in stented ACS patients.

scholarly journals Point-of-care versus central testing of hemoglobin during large volume blood transfusion

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Justin Herman ◽  
Brian Park ◽  
Bharat Awsare ◽  
Frances West ◽  
Denine Crittendon ◽  
...  
Keyword(s):  
Massive Transfusion ◽  
Clinical Laboratory ◽  
Complete Blood Count ◽  
Point Of Care ◽  
Tertiary Care ◽  
Absolute Difference ◽  
Care Hospital ◽  
Specific Patient ◽  
Paired Samples ◽  
Clinically Significant

Abstract Background Point-of-care (POC) hemoglobin testing has the potential to revolutionize massive transfusion strategies. No prior studies have compared POC and central laboratory testing of hemoglobin in patients undergoing massive transfusions. Methods We retrospectively compared the results of our point-of-care hemoglobin test (EPOC®) to our core laboratory complete blood count (CBC) hemoglobin test (Sysmex XE-5000™) in patients undergoing massive transfusion protocols (MTP) for hemorrhage. One hundred seventy paired samples from 90 patients for whom MTP was activated were collected at a single, tertiary care hospital between 10/2011 and 10/2017. Patients had both an EPOC® and CBC hemoglobin performed within 30 min of each other during the MTP. We assessed the accuracy of EPOC® hemoglobin testing using two variables: interchangeability and clinically significant differences from the CBC. The Clinical Laboratory Improvement Amendments (CLIA) proficiency testing criteria defined interchangeability for measurements. Clinically significant differences between the tests were defined by an expert panel. We examined whether these relationships changed as a function of the hemoglobin measured by the EPOC® and specific patient characteristics. Results Fifty one percent (86 of 170) of paired samples’ hemoglobin results had an absolute difference of ≤7 and 73% (124 of 170) fell within ±1 g/dL of each other. The mean difference between EPOC® and CBC hemoglobin had a bias of − 0.268 g/dL (p = 0.002). When the EPOC® hemoglobin was < 7 g/dL, 30% of the hemoglobin values were within ±7, and 57% were within ±1 g/dL. When the measured EPOC® hemoglobin was ≥7 g/dL, 55% of the EPOC® and CBC hemoglobin values were within ±7, and 76% were within ±1 g/dL. EPOC® and CBC hemoglobin values that were within ±1 g/dL varied by patient population: 77% for cardiac surgery, 58% for general surgery, and 72% for non-surgical patients. Conclusions The EPOC® device had minor negative bias, was not interchangeable with the CBC hemoglobin, and was less reliable when the EPOC® value was < 7 g/dL. Clinicians must consider speed versus accuracy, and should check a CBC within 30 min as confirmation when the EPOC® hemoglobin is < 7 g/dL until further prospective trials are performed in this population.

Schnur's Site-Index Curves Formulated for Computer Applications

1985 ◽  
Vol 9 (1) ◽  
pp. 3-5
Author(s):  
Robert M. Farrar
Keyword(s):  
Equation System ◽  
Site Index ◽  
Computer Applications ◽  
Absolute Difference ◽  
Maximum Absolute Difference ◽  
Two Systems ◽  
Pass Through

Abstract Two systems of interpolation equations are offered for the graphic site-index curves of Schnur for even-aged upland oak stands. One is Wiant's equation system, adjusted to pass through site index at index age. The second is similar but some-what more precise. For both, the average absolute difference between equation system and table values is about 0.73 foot and the maximum absolute difference is about 1.9 feet.

scholarly journals Site-index Curve Shape in Spruce

1969 ◽  
Vol 45 (3) ◽  
pp. 184-186 ◽  
Author(s):  
L. Heger
Keyword(s):  
Picea Glauca ◽  
Black Spruce ◽  
White Spruce ◽  
Site Index ◽  
Absolute Difference ◽  
Curve Shape ◽  
Breast Height ◽  
Maximum Absolute Difference ◽  
Site Index Curve ◽  
Index Curve

Sets of site-index curves were prepared from stem analyses of white spruce (Picea glauca (Moench) Voss) and black spruce (P. mariana (Mill.) BSP.) from various regions in the boreal forest of Canada. Ordinates of the site-index curves, computed for 5-year breast-height age intervals up to 75 years, and for 10-foot site-index intervals up to 70 feet, were compared within the species for the same values of site index and age. For breast-height ages below 55 years and for site index below 70 feet, the maximum absolute difference among the ordinates did not exceed 2.0 feet in white spruce, and 1.6 feet in black spruce; the corresponding average deviations were 0.75 and 0.80 feet. For breast-height ages above 55 years, these differences increased with age and, at 75 years, reached 8.8 feet in white spruce, and 3.8 feet in black spruce; the corresponding average deviations were 4.40 and 1.53 feet.

A MODIFIED CORRELATION METHOD FOR T-WAVE ALTERNANS DETECTION

2013 ◽  
Vol 25 (03) ◽  
pp. 1350030
Author(s):  
Xiangkui Wan ◽  
Kanghui Yan ◽  
Minggui Li ◽  
Dingcheng Xiang
Keyword(s):  
Heart Diseases ◽  
Correlation Method ◽  
Absolute Difference ◽  
T Wave ◽  
Formidable Challenge ◽  
Maximum Absolute Difference ◽  
T Wave Alternans ◽  
Improved Performance ◽  
The Time Domain ◽  
Electrocardiogram Ecg

Identification of individuals who are at risk for sudden cardiac death (SCD) remains a formidable challenge. T-wave alternans (TWA) evaluation is emerging as an important tool for risk stratification in patients with heart diseases. Several methods have been developed in recent years to detect and quantify TWA. One such method is known as the correlation method (CM). This method performs well for different levels of TWA and phase shifts in the time domain, but it is sensitive to noise and requires higher quality of electrocardiogram (ECG) signal for test. In this paper, we propose a modified correlation method (MCM) to ensure a robust and accuracy detection of TWA. Compared with CM, MCM add a stage of T-wave curve fitting before media T-wave template, and the TWA magnitude is obtained by meaning the maximum absolute difference between even and odd T-wave. Our assessment study demonstrates the improved performance of the proposed algorithm.

Point of Care Monitoring of the International Normalized Ratio in Patients with Antiphospholipid Antibodies.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1855-1855 ◽  
Author(s):  
Stephanie L. Perry ◽  
Gregory P. Samsa ◽  
Thomas L. Ortel
Keyword(s):  
Whole Blood ◽  
Antiphospholipid Antibodies ◽  
Point Of Care ◽  
Method Comparison ◽  
Correlation Coefficients ◽  
International Normalized Ratio ◽  
Absolute Difference ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Antibody Levels

Abstract Warfarin is effective in decreasing recurrent thrombosis in patients with antiphospholipid antibody syndrome (APS). Antiphospholipid antibodies (APAs) can influence the results of clotting tests in a subset of these patients, which can be a major obstacle in monitoring warfarin. In this study, 59 patients receiving warfarin for a diagnosis of APS were compared to 49 patients receiving warfarin for atrial fibrillation (AF) with regard to consistency between International Normalized Ratio (INR) results obtained from two Point of Care (POC) monitors and a standard plasma-based method used in the coagulation laboratory. INR results were obtained using a fingerstick for whole blood on the ProTime® monitor (International Technidyne Corp, ITC, Edison, NJ) and by venipuncture using both citrated and non-citrated whole-blood on a HEMOCHRON®Signature (Hr. Sig.) monitor (ITC). Parallel INR measurements were obtained on an MDA-180 analyzer (bioMeriéux, Durham, NC), using Simplastin-HTF. Additional tests included chromogenic factor Xa (CFXa) and tests for APAs (antiphospholipid, anti-β2-glycoprotein I [β2GPI], and antiprothrombin ELISA’s). Insufficient blood was obtained from 5 patients for testing with the ProTime® (3 AF, 2 APS). For an additional 5 patients, all with APS, sufficient blood was obtained, but an INR could not be determined by the instrument (8%). Single INR results on the ProTime® were obtained from 2 of these patients on repeat testing. The data were analyzed with the 100 patients who had at least one INR result with the ProTime®. Analyses included determination of the means of absolute differences between each method of obtaining INR results, correlations between INR results and CFXa results, and correlations with APAs results. Systematic differences were found for each INR method comparison, ranging from 0.24±0.23 to 0.41±0.29, with correlation coefficients ranging from 0.54 to 0.80. The differences were similar for AF and APS patients for all INR comparisons with the exception of the results comparing the standard plasma-based method with the ProTime®, which showed a mean absolute difference of 0.24 for AF patients and 0.39 for APS patients (p=0.01). Preliminary data analysis did not show perfect calibration between the CFXa and the different methods for obtaining INR results for either patient group. Correlation coefficients ranged from 0.3 to 0.7 when comparing CFXa to each INR method, and the best correlation was between the standard plasma INR and the CFXa for patients with AF (0.65). Review of testing for APAs at the time of INR testing revealed that 10 patients with AF had elevated antibody levels (20%; all by antiphospholipid ELISA only and most only minimally elevated), compared to 27 patients with APAs (45%, with 21 having elevated anti-β2 GPI antibody levels). The five patients with non-measurable ProTime® INRs had elevated anti-β2GPI levels and generally higher INRs with the Hr. Sig., but CFXa results were not supratherapeutic. In conclusion, these results suggest that in a subset of patients with APAs, the ProTime® will not yield any results and can not be used due to the internal QC set of the monitor. APA testing did not specifically identify which APS patients would most likely have problems with INR testing.

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