Point-of-care microvolume cytometer measures platelet counts with high accuracy from capillary blood

Background Point-of-care (PoC) testing of platelet count (PLT) provides real-time data for rapid decision making. The goal of this study is to evaluate the accuracy and precision of platelet counting using a new microvolume (8 μL), absolute counting, 1.5 kg cytometry-based blood analyzer, the rHEALTH ONE (rHEALTH) in comparison with the International Society of Laboratory Hematology (ISLH) platelet method, which uses a cytometer and an impedance analyzer. Methods Inclusion eligibility were healthy adults (M/F) ages 18–80 for donation of fingerprick and venous blood samples. Samples were from a random N = 31 volunteers from a single U.S. site. Samples were serially diluted to test thrombocytopenic ranges. Interfering substances and conditions were tested, including RBC fragments, platelet fragments, cholesterol, triglycerides, lipids, anti-platelet antibodies, and temperature. Results The concordance between the rHEALTH and ISLH methods had a slope = 1.030 and R2 = 0.9684. The rHEALTH method showed a correlation between capillary and venous blood samples (slope = 0.9514 and R2 = 0.9684). Certain interferents changed platelet recovery: RBC fragments and anti-platelet antibodies with the ISLH method; platelet fragments and anti-platelet antibodies on the rHEALTH; and RBC fragments, platelets fragments, triglycerides and LDL on the clinical impedance analyzer. The rHEALTH’s precision ranged from 3.1–8.0%, and the ISLH from 1.0–10.5%. Conclusions The rHEALTH method provides similar results with the reference method and good correlation between adult capillary and venous blood samples. This demonstrates the ability of the rHEALTH to provide point-of-care assessment of normal and thrombocytopenic platelet counts from fingerprick blood with high precision and limited interferences.

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The Effect of Venous Occlusion on the Sequestration of Blood Platelets

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649022 ◽

1972 ◽

Vol 28 (03) ◽

pp. 383-392 ◽

Cited By ~ 1

Author(s):

J Hladovec ◽

Z Koleilat ◽

I Přerovský

Keyword(s):

Blood Platelets ◽

Venous Blood ◽

Venous Occlusion ◽

Blood Samples ◽

Pronounced Decrease ◽

Platelet Counts ◽

Human Volunteers ◽

Opposite Change

SummaryThe venous occlusion of all four legs in rats caused a highly significant decrease of platelet counts in venous blood especially after the correction for an opposite change in haematocrit. A very pronounced decrease in platelets was observed in human volunteers after a venostasis in one arm in the blood drawn from the occluded limb just before the release of occlusion. Similar decreases were found after a venostasis of both legs in postocclusion blood samples. The decrease in blood platelets results from temporary sequestration in the occluded limbs. The decreases of platelets after a 10 min occlusion of both legs are more pronounced in patients with post thrombotic states.

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Blood Glucose Assay Using Dextrostix and a Reflectance Meter

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456327200900144 ◽

1972 ◽

Vol 9 (1-6) ◽

pp. 91-94 ◽

Cited By ~ 6

Author(s):

I. W. Percy-Robb ◽

R. S. McMaster ◽

A. D. B. Harrower ◽

L. J. P. Duncan

Keyword(s):

Blood Glucose ◽

Venous Blood ◽

Reference Method ◽

Capillary Blood ◽

Blood Samples ◽

Laboratory Staff ◽

Glucose Assay ◽

Reflectance Meter ◽

High Degree ◽

Blood Glucose Concentrations

The ‘Dextrostix’-reflectance meter system for blood glucose analysis has been evaluated using a blood glucose reference method. A high degree of concordance between the two methods was obtained when analyses were performed by skilled laboratory staff on venous blood samples containing fluoride, with a 75 s contact time. Skilled laboratory staff performed significantly better than unskilled staff. Capillary blood glucose concentrations correlated poorly with concentrations in venous blood samples taken at the same time as the capillary blood.

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Accuracy of single intravenous access iohexol GFR in children is hampered by marker contamination

Scientific Reports ◽

10.1038/s41598-021-02759-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Thea Tislevoll Eide ◽

Karl Ove Hufthammer ◽

Atle Brun ◽

Damien Brackman ◽

Einar Svarstad ◽

...

Keyword(s):

Clinical Trial ◽

Filtration Rate ◽

Venous Blood ◽

Reference Method ◽

Blood Sampling ◽

Clinical Trial Registration ◽

Blood Samples ◽

Intravenous Access ◽

Time Points ◽

Rank 2

AbstractMeasurement of glomerular filtration rate (GFR) in children by iohexol injection and blood sampling from the contralateral arm is widely used. A single intravenous access for iohexol injection and subsequent blood sampling has the obvious advantages of being less painful and easier to perform. The purpose of our study was to determine if blood samples drawn from the injection access are feasible and accurate for iohexol GFR (iGFR) measurements. Thirty-one children, median age 10.5 (range 6–17) years, with chronic kidney disease were given a bolus of iohexol followed by extended saline flushing and subsequent venous blood samples collected from the injection access as well as from a cannula in the contralateral arm, the latter serving as the reference method. Paired venous blood samples were collected at four time points (2, 3, 3.5 and 4 h) after the iohexol bolus. Blood sample discarding preceded and saline flushing followed each blood sampling to avoid marker contamination. iGFR based on samples drawn from the injection access at 2 and 3 h showed significantly lower iGFR than measurement from the contralateral arm (p < 0.01). Singlepoint iGFR did not differ significantly after 3–4 repeated procedures of blood discarding and saline flusing (3.5 and 4 h). Despite thorough saline flushing there is still a relatively high risk of falsely low iGFR due to marker contamination in blood samples from the injection site. Hence, blood sampling from a second intravenous access is recommended for routine iohexol GFR measurements in children.Clinical trial registration: ClinicalTrials.gov, Identifier NCT01092260, https://clinicaltrials.gov/ct2/show/NCT01092260?term=tondel&rank=2.

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Accuracy and precision of analyses for total cholesterol as measured with the Reflotron cholesterol method.

Clinical Chemistry ◽

10.1093/clinchem/35.8.1734 ◽

1989 ◽

Vol 35 (8) ◽

pp. 1734-1739 ◽

Cited By ~ 21

Author(s):

P S Bachorik ◽

R H Bradford ◽

T Cole ◽

I Frantz ◽

A M Gotto ◽

...

Keyword(s):

Plasma Cholesterol ◽

Venous Blood ◽

Reference Method ◽

Capillary Blood ◽

Average Difference ◽

Blood Samples ◽

Laboratory Values ◽

Accuracy And Precision ◽

Single Finger ◽

Made In

Abstract We compared plasma cholesterol measurements made with the Boehringer Mannheim Reflotron reflectance photometric analyzer in 1298 capillary blood samples with measurements made in venous blood samples collected at the same time and analyzed in four standardized Lipid Research Clinics laboratories. The Reflotron measurements averaged 0.8% to 7.8% lower than the laboratory values. Correlations (r) between the two sets of measurements ranged from 0.92 to 0.96. In some samples, however, the Reflotron values differed from the laboratory values by greater than or equal to 12%; the cholesterol concentrations in these samples tended to be higher than in those for which better agreement was observed. The smaller negative biases were observed when test strips were used that were calibrated with reference to the Centers for Disease Control Reference Method for cholesterol. The agreement between sequential Reflotron values averaged less than or equal to 4.3%. There was an average difference of less than or equal to 1.0% between Reflotron measurements made in each of two sequential capillary blood samples taken from a single finger puncture.

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Measurement accuracy of two professional-use systems for point-of-care testing of blood glucose

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2019-0549 ◽

2020 ◽

Vol 58 (3) ◽

pp. 445-455

Author(s):

Annette Baumstark ◽

Nina Jendrike ◽

Ulrike Kamecke ◽

Christina Liebing ◽

Stefan Pleus ◽

...

Keyword(s):

Blood Glucose ◽

Point Of Care ◽

Venous Blood ◽

Laboratory Method ◽

Sample Type ◽

Point Of Care Testing ◽

Blood Samples ◽

Testing Procedures ◽

Grid Analysis ◽

Error Grid

AbstractBackgroundThe professional-use systems HemoCue® Glucose 201+ (HC201+) and HemoCue® Glucose 201 RT (HC201RT) are widely used for point-of-care testing (POCT) of blood glucose (BG). HC201RT utilizes unit-use microcuvettes which can be stored at room temperature, whereas HC201+ microcuvettes have to be stored at <8 °C. In this study, system accuracy of HC201+ and HC201RT was evaluated using capillary and venous blood samples.MethodsFor each system, two reagent system lots were evaluated within a period of 2 years based on testing procedures of ISO 15197:2013, a standard applicable for self-monitoring of blood glucose (SMBG) systems. For each reagent system lot, the investigation was performed by using 100 capillary and 95 to 99 venous blood samples. Comparison measurements were performed with a hexokinase laboratory method. Accuracy criteria of ISO 15197:2013 and POCT12-A3 were applied. In addition, bias was analyzed according to Bland and Altman, and error grid analysis was performed.ResultsWhen measuring capillary samples, both systems fulfilled accuracy requirements of ISO 15197:2013 and POCT12-A3 with the investigated reagent system lots. When measuring venous samples, only HC201+ fulfilled these requirements. Bias between HC201+ and reference measurements was more consistent over venous and capillary samples and microcuvette lots than for HC201RT. Error grid analysis showed that clinical actions might have been different depending on which system was used.ConclusionsIn this study, HC201+ showed a high level of accuracy irrespective of the sample type (capillary or venous). In contrast, HC201RT measurement results were markedly affected by the type of sample.

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Comparative Evaluation of Hematologic Analyzers Advia® 120, Advia® 2120 and Pentra® 120DX for Platelet Counts below 40 X 109/L.

Blood ◽

10.1182/blood.v106.11.1256.1256 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1256-1256

Author(s):

Josep M. Jou ◽

Fulgencio Navalon ◽

Ester Jiménez ◽

Maribel Diaz-Ricart ◽

Rosa Brugues ◽

...

Keyword(s):

Flow Cytometry ◽

Linear Regression ◽

Reference Method ◽

Cell Counting ◽

Average Difference ◽

Double Labeling ◽

Blood Samples ◽

Platelet Counts ◽

Flow Cytometric Method ◽

Advia 120

Abstract More aggressive therapies used for treatment of oncohematological malignancies or control of immune responses are resulting in an increased frequency of platelet counts below the 50 x 109/L limit. The recommended reference method for platelet counts was tedious and showed low reproducibility until now. In the last 2 years, flow cytometry based techniques combined with specific monoclonal antibodies (MoAbs) have been accepted as reference method. We have evaluated the accuracy for low platelet counts of several hematologic analyzers currently used in our laboratories. The new reference method approved by ISLH, ICSH y NCCLS is based on double labeling of platelets using MoAbs directed to CD41 and CD61 followed by flow cytometry analysis. Absolute platelet counts are calculated using a ratio with red blod cell (RBC) counts provided by the hematological analyzers. In our studies, 50 blood samples with platelet counts ranging from 1.5 to 39.4 x109/L were processed in duplicate through 1 Advia 2120 (Bayer Diagnostics), 2 Advia 120 (Bayer Diagnostics) and 2 Pentra 120 DX (Horiba-ABX Diagnostics). Advia analyzers use laser-based technology while Pentra analyzers use impedance one for cell counting. All samples were also processed through the reference flow cytometric method, being platelets identified by their double labeling for CD41 and CD61. The minimal number of platelets acquired in the platelet region was established at 1000. Absolute platelet counts were calculated using RBC counts provided by the respective analyzers. All blood samples were processed within 6 hours from phlebotomy. Statistical methods applied included: coefficient of variation (%CV), coefficient of correlation (r ), linear regression, Passing-Bablock (P-B) regression and Bland-Altman test. Precision of each analyzer was obtained by processing in 10 times different blood samples with counts from 4 to 39 x 109/L. Global results were evaluated, though special attention was paid to subgroups of results below or above 20 x 109/L. Correlation between reference values and counts provided by the Advia 2120 was 0.945 with a linear regression of 0.987x+2.9. P-B correlation was good and the average difference was 2.7 x 109/L. In the subgroup of samples with counts below 20 x 109/L correlation was 0.874 with 1.00x+2.7. P-B was correct and the average difference was 2.8 x 109/L. Results with Advia 120 were always similar to those calculated with the Advia 2120, though the average difference was slightly lower with a value of 1.7 x 109/L. Precision (CV) was 16% for platelet count levels at 4 x 109/L, 12% for those at 13 x 109/L and 4% for those at 39 x 109/L. Correlation with Pentra 120 Dx was 0.937 with a linear regression of 0.894x+2.7, the P-B was acceptable with an average difference of 1.2 x 109/L. Correlation index was 0.824 with a linear regression of 0.88x+2.8 for platelet counts below 20 x 109/L, average difference was of 1.4 x 109/L and a correct P-B. Precision (CV) ranged from 26% at 4 x 109/L and 8% at 20 x 109/L platelet counts. Our data demonstrate that hematological analyzers evaluated provided very reliable results at low platelet counts. Advia and Pentra analyzers investigated tend to over calculate the number of platelets (2.5 and 1.4 x109/L respectively). Correlation scattering was slightly superior with the Pentra analyzer. Overall reproducibility for low platelet counts was excellent for both laser and impedance technologies tested.

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Assessment of a glycated hemoglobin point-of-care analyzer (A1CNow+) in comparison with an immunoturbidimetric method: a diagnostic accuracy study

Sao Paulo Medical Journal ◽

10.1590/1516-3180.2013.9110911 ◽

2015 ◽

Vol 133 (6) ◽

pp. 460-464 ◽

Cited By ~ 3

Author(s):

Aurélie Affret ◽

Luiz Henrique Maciel Griz ◽

Eduarda Ângela Pessoa Cesse ◽

Yuri da Silva Specht ◽

Eduardo Maia Freese de Carvalho ◽

...

Keyword(s):

Glycemic Control ◽

Sensitivity And Specificity ◽

Glycated Hemoglobin ◽

Point Of Care ◽

Venous Blood ◽

Reference Method ◽

University Hospital ◽

Diabetic Patients ◽

Good Glycemic Control ◽

Accuracy Study

CONTEXT AND OBJECTIVE: To monitor glycemic control in diabetic patients, regular measurement of glycated hemoglobin (HbA1c) is recommended, but this can be difficult in remote places without access to laboratories. Portable point-of-care testing devices can prove a useful alternative. Our study aimed to assess the performance of one of them: A1CNow+, from Bayer. DESIGN AND SETTING: Cross-sectional accuracy study conducted at a university hospital in Brazil. METHODS: We made three successive measurements of capillary HbA1c using the A1CNow+ in 55 diabetic volunteers, while the same measurement was made on venous blood using the hospital reference method (Vitros 5,1 FS). We used the Bland-Altman graphical method to assess the A1CNow+ in relation to the Vitros 5,1 FS method. We also evaluated clinical usefulness by calculating the sensitivity and specificity of A1CNow+ for detecting patients with HbA1c lower than 7%, which is the usual limit for good glycemic control. RESULTS: The coefficient of variation between repeat testing for the A1CNow+ was 3.6%. The mean difference between A1CNow+ and Vitros 5,1 FS was +0.67% (95% confidence interval, CI: +0.52 to +0.81). The agreement limits of our Bland-Altman graph were -0.45 (95% CI: -0.71 to -0.19) and +1.82 (95% CI: +1.52 to +2.05). The sensitivity and specificity in relation to the 7% limit were respectively 100% and 67.7%. CONCLUSIONS: Although the A1CNow+ had good sensitivity, its accuracy was insufficient for use as a replacement for laboratory measurements of HbA1c, for glycemic control monitoring in diabetic patients.

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Comparison between B·R·A·H·M·S PCT direct, a new sensitive point-of-care testing device for rapid quantification of procalcitonin in emergency department patients and established reference methods – a prospective multinational trial

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2015-0437 ◽

2016 ◽

Vol 54 (4) ◽

Cited By ~ 14

Author(s):

Alexander Kutz ◽

Pierre Hausfater ◽

Michael Oppert ◽

Murat Alan ◽

Eva Grolimund ◽

...

Keyword(s):

Emergency Department ◽

Diagnostic Accuracy ◽

Whole Blood ◽

Point Of Care ◽

Venous Blood ◽

Reference Method ◽

Point Of Care Test ◽

Emergency Department Patients ◽

Work Up

AbstractProcalcitonin (PCT) is increasingly being used for the diagnostic and prognostic work up of patients with suspected infections in the emergency department (ED). Recently, B·R·A·H·M·S PCT direct, the first high sensitive point-of-care test (POCT), has been developed for fast PCT measurement on capillary or venous blood samples.This is a prospective, international comparison study conducted in three European EDs. Consecutive patients with suspicion of bacterial infection were included. Duplicate determination of PCT was performed in capillary (fingertip) and venous whole blood (EDTA), and compared to the reference method. The diagnostic accuracy was evaluated by correlation and concordance analyses.Three hundred and three patients were included over a 6-month period (60.4% male, median age 65.2 years). The correlation between capillary or venous whole blood and the reference method was excellent: rThis study found a high diagnostic accuracy and a faster time to result of B·R·A·H·M·S PCT direct in the ED setting, allowing shortening time to therapy and a more wide-spread use of PCT.

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Automated Optical Counting of Blood Platelets

Blood ◽

10.1182/blood.v38.4.422.422 ◽

1971 ◽

Vol 38 (4) ◽

pp. 422-430 ◽

Cited By ~ 10

Author(s):

GEOFFREY M. BRITTIN ◽

SHIRLEY A. DEW ◽

ELVI K. FEWELL

Keyword(s):

Whole Blood ◽

Blood Platelets ◽

Venous Blood ◽

Human Platelets ◽

Blood Samples ◽

Platelet Counts ◽

Large Numbers ◽

Significant Difference ◽

Electronic Method ◽

Electronic Counting

Abstract We have evaluated the use of an optical particle counter to perform automated platelet counts on whole blood. The erythrocytes were lysed by dilution of whole blood with 2 M urea and the remaining platelets and leukocytes were enumerated by a darkfield microscope optical system that detects light diffracted by them. A suspension of fixed human platelets available commercially was highly satisfactory for standardization. The method gave accurate and reproducible platelet counts, comparable with those of electronic particle counting on venous blood and substantially more reliable platelet counts on thrombocytopenic and finger-puncture blood samples. We believe that errors resulting from the electronic method were caused by technical difficulties of sample handling and not to an intrinsic error in electronic counting. By using the automated optical method we found no significant difference between the platelet counts of capillary and venous blood, although capillary platelet counts had twice the variability of venous counts. The optical technique has important advantages over electronic platelet counting, and its superiority appears to be due to the ability to count platelets in diluted whole blood rather than in plasma. It should prove especially useful in performing the large numbers of platelet counts on thrombocytopenic and finger-puncture blood samples that are increasingly important for management of patients receiving chemotherapy.

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Fingerstick Precision and Total Error of a Point-of-Care HbA1c Test

Journal of Diabetes Science and Technology ◽

10.1177/1932296819831273 ◽

2019 ◽

Vol 14 (5) ◽

pp. 890-895 ◽

Cited By ~ 3

Author(s):

William D. Arnold ◽

Kenneth Kupfer ◽

Monica Hvidsten Swensen ◽

Kyle S. Fortner ◽

Harold E. Bays ◽

...

Keyword(s):

Whole Blood ◽

Point Of Care ◽

Total Error ◽

Venous Blood ◽

Undiagnosed Diabetes ◽

Components Of Variance ◽

Blood Samples ◽

High Hba1c ◽

Prior Investigation ◽

Whole Blood Samples

Background: Point-of-care (POC) HbA1c tests hold the promise of reducing the rates of undiagnosed diabetes, provided they exhibit acceptable analytical performance. The precision and total error of the POC (Afinion™ HbA1c Dx) test were investigated using whole blood samples obtained by fingerstick and venipuncture. Methods: Fingerstick samples spanning the assay range were collected from 61 subjects at three representative POC sites. At each site, six fingerstick samples were obtained from each subject and tested on the POC test across two (Afinion AS100) instruments. Repeatability, between-operator, and between-instrument components of variance were calculated using analysis of variance (ANOVA). Four venous samples (low, threshold, medium, and high HbA1c) were measured in duplicate across three instruments using three reagent lots, twice per day over 20-days. Repeatability, between-run, between-day, between-lot, and between-instrument components of variance were calculated. These fingerstick and venous blood results, combined with estimates of imprecision and bias from a prior investigation, allowed for the calculation of the total coefficient of variation (CV) and total error of the POC test using fingerstick and venous whole blood samples. Results: The total imprecision ranged from 1.30% to 2.03% CV using fingerstick samples and from 1.31% to 1.64% CV using venous samples. The total error ranged from 2.87% to 4.75% using fingerstick samples and from 2.93% to 3.80% using venous samples. Conclusions: The POC test evaluated here is precise across its measuring range using both fingerstick and venous whole blood. The calculated total error of the test is well under the accepted quality requirement of ≤6%.

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