Evaluation of Friedewald's Formula for Plasma LDL-Cholesterol Estimation.

BACKGROUND: Low-density lipoprotein cholesterol (LDL-C) can contribute to atherosclerosis if it is oxidized within the walls of arteries. Therefore, LDL-C plays an important role in cardiovascular disease risk assessment and prevention. The current study aims to evaluate the validity of Friedewald's formula in the Taiwanese population. METHODS: In this analytical cross-sectional study, a data set containing 31,729 results was used and lipid profiles of all samples were measured using the Beckman Coulter AU680 clinical chemistry analyzer. This study was conducted from September 2016 to August 2019. RESULTS: The agreement between the direct and calculated LDL-C was significant with Pearson's correlation coefficient (r) of 0.904 (p < 0.001). Mean LDL-C levels were 99.3 ± 32.8 mg/dL and 95.3 ± 37.6 mg/dL for direct and calculated LDC-C, respectively. CONCLUSIONS: Good agreement was observed between direct and calculated LDC-C. Therefore, it can be concluded that Friedewald's formula is applicable in LDL-C estimation when the direct method is not affordable.

Closed Bipolar Electrode-Enabled Electrochromic Sensing of Multiple Metabolites in Whole Blood.

We report a closed bipolar electrode (CBE)-based sensing platform for the detection of diagnostic metabolites in undiluted whole human blood. The sensor is enabled by electrode chemistry based on: (1) a mixed layer of blood-compatible adsorption-resistant phosphorylcholine (PPC) and phenylbutyric acid (PBA), (2) ferrocene (Fc) redox mediators, and (3) immobilized redox-active enzymes. This scheme is designed to overcome nonspecific protein adsorption and amplify sensing currents in whole human fluids. The scheme also incorporates a diffusing mediator to increase electronic communication between the immobilized redox enzyme and the working electrode. The use of both bound and freely diffusing mediators is synergistic in producing the electrochemical response. The sensor is realized by linking the analyte cell, containing the specific electrode surface architecture, through a CBE to a reporter cell containing the electrochromic reporter, methyl viologen (MV). The colorless-to-purple color change accompanying the 1e- reduction of MV2+ is captured using a smartphone camera. Subsequent red-green-blue analysis is performed on the acquired images to determine cholesterol, glucose, and lactate concentrations in whole blood. The CBE blood metabolite sensor produces a linear color change at clinically relevant concentration ranges for all metabolites with good reproducibility (∼5% or better) and with limits of detection of 79 µM for cholesterol, 59 µM for glucose, and 86 µM for lactate. Finally, metabolite concentration measurements from the CBE blood metabolite sensor are compared with results from commercially available FDA-approved blood cholesterol, glucose, and lactate meters, with an average difference of ∼3.5% across all three metabolites in the ranges studied.

TBISTAT: An open-source, wireless portable, electrochemical impedance spectroscopy capable potentiostat for the point-of-care detection of S100B in plasma samples.

Point-of-Care (POC) testing for biomarker detection demands techniques that are easy to use, readily available, low-cost, and with rapid response times. This paper describes the development of a fully open-source, modular, wireless, battery-powered, smartphone-controlled, low-cost potentiostat capable of conducting electrochemical impedance spectroscopy for the electrochemical detection of the S100B protein captured in an ANTI-S100B functionalized thin-film gold interdigitated electrode platform to support traumatic brain injury diagnosis and treatment. EIS results from the developed potentiostat were validated with a commercial benchtop potentiostat by comparing impedance magnitude and phase values along the EIS frequency range. In addition, an experimental design was performed for detecting S100B in spiked human plasma samples with S100B concentrations of clinical utility, and a calibration curve was found for quantifying S100B detection. No statistically significant differences were found between EIS results from the developed potentiostat and the commercial potentiostat. Statistically significant differences in the changes in charge transfer resistance signal between each tested S100B concentration (p < 0.05) were found, with a limit of detection of 35.73 pg/mL. The modularity of the proposed potentiostat allows easier component changes according to the application demands in power, frequency excitation ranges, wireless communication protocol, signal amplification and transduction, precision, and sampling frequency of ADC, among others, when compared to state-of-the-art open-source EIS potentiostats. In addition, the use of minimal, easy acquirable open-source hardware and software, high-level filtering, accurate ADC, Fast Fourier Transform with low spectral leakage, wireless communication, and the simple user interface provides a framework for facilitating EIS analysis and developing new affordable instrumentation for POC biosensors integrated systems.

Evaluation of Trueness and Precision of a Bench-Top Laboratory Glucose Analyzer Using Reference Materials.

SUPER GL compact is a bench-top analyzer for glucose, lactate, and hemoglobin concentrations. Glucose measurements in the biosensor are based on an enzymatic-amperometric reaction of glucose with glucose oxidase.In this study, trueness and precision were assessed with Standard Reference Material 965b (National Institute of Standards and Technology, Gaithersburg, MD) for 2 SUPER GL compact (S1 and S2) and 1 YSI 2300 STAT Plus (Y) device, using a protocol based on CLSI EP05-A3.Precision was similar among S1, S2, and Y. S1 and S2 exhibited negative bias at low concentrations and positive bias at high concentrations, whereas Y showed negative bias that increased with higher concentrations. Overall, SUPER GL compact's performance was comparable to that of YSI 2300 STAT Plus.

Establishment of a new protein C detection system based on chromogenic substrate assay and its clinical diagnostic value for deep vein thrombosis.

BACKGROUND: Deficiency of protein C (PC) affects the balance between blood coagulation and fibrinolysis in the human body. Chromogenic-based assay is recommended as the preferred screening method for detecting PC deficiency. We established a PC detection system based on the chromogenic substrate assay. METHODS: First, a kit for the determination of PC activity in plasma was elaborately developed and its reaction parameters on XL-3200c were explored. Then, we evaluated its performance and collected specimens to compare the test results obtained with those of the Siemens detection system. Finally, the clinical diagnostic efficacy of this detection system for deep vein thrombosis (DVT) was assessed. RESULTS: Optimum conditions for PC detection were 0.25-0.1 U/ml protein C activator Protac® and 2.5-1 mM Pefachrome® PCa5297. The composition and concentration ranges of buffer substances and stabilizers in the kit were also explored. Satisfactory results were observed in performance evaluation. The test results of the newly built detection system were highly correlated with those of the Siemens detection system (R2  = 0.9771 in the control group and R2  = 0.9776 in the DVT group), and Bland-Altman plots also showed high consistency between the two detection systems. In addition, the area under the curve (AUC) of the newly built PC detection system for DVT was 0.888, indicating this system could effectively improve the diagnostic sensitivity and specificity for DVT. CONCLUSION: In this study, a sensitive, wide linear range and reliable PC activity detection system were established.

Development of a target product profile for a point-of-care cardiometabolic device.

INTRODUCTION: Multi-parameter diagnostic devices can simplify cardiometabolic disease diagnosis. However, existing devices may not be suitable for use in low-resource settings, where the burden of non-communicable diseases is high. Here we describe the development of a target product profile (TPP) for a point-of-care multi-parameter device for detection of biomarkers for cardiovascular disease and metabolic disorders, including diabetes, in primary care settings in low- and middle-income countries (LMICs). METHODS: A draft TPP developed by an expert group was reviewed through an online survey and semi-structured expert interviews to identify device characteristics requiring refinement. The draft TPP included 41 characteristics with minimal and optimal requirements; characteristics with an agreement level for either requirement of ≤ 85% in either the survey or among interviewees were further discussed by the expert group and amended as appropriate. RESULTS: Twenty people responded to the online survey and 18 experts participated in the interviews. Twenty-two characteristics had an agreement level of ≤ 85% in either the online survey or interviews. The final TPP defines the device as intended to be used for basic diagnosis and management of cardiometabolic disorders (lipids, glucose, HbA1c, and creatinine) as minimal requirement, and offering an expanded test menu for wider cardiometabolic disease management as optimal requirement. To be suitable, the device should be intended for level 1 healthcare settings or lower, used by minimally trained healthcare workers and allow testing using self-contained cartridges or strips without the need for additional reagents. Throughput should be one sample at a time in a single or multi-analyte cartridge, or optimally enable testing of several samples and analytes in parallel with random access. CONCLUSION: This TPP will inform developers of cardiometabolic multi-parameter devices for LMIC settings, and will support decision makers in the evaluation of existing and future devices.

Simultaneous point-of-care testing of blood lipid profile and glucose: Performance evaluation of the GCare Lipid Analyzer.

BACKGROUND: Point-of-care (POC) testing provides quick results and includes tests for blood glucose and lipid profiles. We evaluated the newly developed POC device, the GCare Lipid Analyzer, which is used to measure glucose, total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) levels. METHODS: Venous and capillary blood samples were collected from patients who visited Korea University Guro Hospital. The results obtained using the GCare Lipid Analyzer were compared with those obtained using the TBA 2000FR chemistry analyzer and YSI 2300 STAT Plus analyzer. The glucose system evaluation process was based on the International Organization for Standardization 15197:2013 guidelines. RESULTS: The correlation coefficients (R) for TC, TG, and HDL-C were 0.965, 0.969, and 0.943 in capillary blood and 0.969, 0.990, and 0.956 in venous blood, respectively. The total errors for TC, TG, and HDL-C of the lipid profile using venous blood were all acceptable at 6.6%, 9.3%, and 11.6%, respectively. For glucose concentrations <100 mg/dl, 96.1% of the measured glucose levels were within ±15 mg/dl in venous samples and 100% were within ±15 mg/dl in capillary samples. For glucose concentrations ≥100 mg/dl, 100% and 99.5% of the measured glucose levels were within 15% for venous and capillary blood, respectively. CONCLUSION: The performance of the GCare Lipid Analyzer is acceptable for both blood glucose and lipid profile testing, indicating that it is reliable for use in patients with diabetic dyslipidemia.

Establishing paediatric reference intervals for thyroid function tests in Croatian population on the Abbott Architect i2000.

INTRODUCTION: Evaluation of thyroid function is often requested and therefore defining paediatric reference intervals (RIs) is of vital importance. Currently, there is a distinct lack of paediatric RIs for thyroid function tests in Croatia. Thus, we established RIs for thyroid stimulating hormone (TSH), total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3) and free thyroxine (FT4) in the Croatian paediatric population. MATERIALS AND METHODS: Reference intervals were calculated from 397 apparently healthy children, aged from 2 days to < 19 years. Serum samples were analysed for thyroid function tests on the Abbott Architect i2000. Age- and sex-specific 95% RIs with 90% confidence intervals were established according to Clinical and Laboratory Standards Institute guidelines. To express the magnitude of sex and age variation, standard deviation ratio (SDR) was calculated using two-level nested ANOVA. The criterion for considering partitioning reference values was set to SDR > 0.3. RESULTS: All thyroid function tests required age partitioning, confirmed by SDR above 0.3. There was no need for sex partitioning, confirmed by SDR below 0.3. Still, FT3 was partitioned due to visually noticeable sex related difference for the oldest group (12 years to < 19 years). CONCLUSION: This is the first study to establish RIs for thyroid function tests in the Croatian paediatric population. We propose RIs for widely used Abbott platform, thus giving laboratories method- and population-specific paediatric RIs for thyroid function tests that should improve clinical test interpretation.

Correlation between human health and reactive oxygen species produced in blood: a long-term chemiluminescence and fluorescence analysis.

The previous slide-glass type system could simultaneously detect reactive and highly reactive oxygen species, i.e., superoxide radicals (O2-·) and hypochlorite ions (OCl-) elicited from leucocytes in sample blood, but had some drawbacks, i.e., signal noise from air-flow stirring, potential biohazard risks, etc. because of open samples placed on a slide glass. We overcame these drawbacks by adopting a fluidic-chip container in a new system, which resulted in higher sensitivity and more stable measurements. Using the new system, we conducted a pilot study on nominally healthy volunteers to find whether or not the monitored activities of leukocytes can distinguish more or less unhealthy conditions from healthy ones. At first, healthy volunteers of both genders and of various ages showed that the fluctuation magnitudes (%) of O2-· and OCl- were nearly similar to each other and to that of the neutrophil count fluctuation. These parameters sometimes exceeded the healthy fluctuation range. By comparing these large fluctuations with the data of an inflammation marker C-reactive protein (CRP), the neutrophil count fluctuation and the timings/symptoms of abnormalities found in questionnaire, we could gain information suggesting the factors causing the large fluctuations. The new system could detect bodily abnormalities earlier than CRP or self-aware symptoms.

Interference of eltrombopag with bilirubin measurements on the Vitros 5600 analyzer.

BACKGROUND: Eltrombopag is a thrombopoietin-receptor agonist used to restore platelet count to hemostatic levels in chronic immune thrombocytopenia. The drug has shown to have hepatobiliary adverse effects, but also positive interference with the analytical measurement of bilirubin. Understanding the degree of interference of this drug with bilirubin testing becomes relevant in the clinical management of these patients. METHODS: Eltrombopag at concentrations ranging from 10 to 150 µg/ml was spiked into plasma samples with different baseline concentrations of bilirubin. Total bilirubin, conjugated, and unconjugated bilirubin were measured for each sample using VITROS TBILI and BuBc slides on the Vitros 5600 automated chemistry platform, and interference was assessed. RESULTS: Plasma samples spiked with eltrombopag yielded falsely elevated bilirubin measurements compared to baseline, with the degree of elevation increasing with greater concentrations of eltrombopag. Bilirubin values were increased relative to baseline across all groups, except in conjugated bilirubin measurements in samples with low baseline conjugated bilirubin. For samples with low total bilirubin at baseline, >100 µg/ml of eltrombopag resulted in an error of >+0.6 mg/dl on the measured total bilirubin. For samples with low unconjugated bilirubin at baseline, the error for the same concentrations was >+0.7 mg/dl. CONCLUSION: Our results show that, at supra-physiologically high concentrations, eltrombopag can positively interfere with bilirubin measurements on Vitros 5600 platform.

Facile synthesis of bifunctional polymer monolithic column for tunable and specific capture of glycoproteins and phosphoproteins.

Efficiently tunable capture of the glycosylated/phosphorylated proteins is critical to meet the need of in-depth glycoproteome and phosphoproteome studies. Reported here is a new bifunctional polymer monolithic column by introducing benzeneboronic acid and phosphonic acid onto monolithic column (denoted as poly (EDMA-co-VPBA-co-VPA) monolith) for tunable and specific enrichment of glycoproteins and phosphoproteins via switching different mobile phases. Based on boronate affinity and immobilized metal affinity, the as-prepared poly (EDMA-co-VPBA-co-VPA) monolith exhibited superior performance in selective separation of small molecules and biomacromolecules containing cis-diol/phosphate groups or not. And the frontal chromatography analysis showed that the binding capacity of the poly (EDMA-co-VPBA-co-VPA) monolith towards horseradish peroxidase (HRP, glycoprotein) or ß-casein (phosphoprotein) is four-fold higher than that of bovine serum albumin (BSA, non-glycosylated/phosphorylated protein). Furthermore, combined with mass spectrometry identification, the successful application in specific enrichment of glycopeptides/phosphopeptides from tryptic digests of HRP/ß-casein and direct capture of low abundant endogenous phosphopeptides from human serum proved great practicability in complex samples. This study provides a novel insight for fabricating the monolithic columns with multifunctionalization to facilitate further post-translational modification (PTM)-proteomics development.

Establishment of time-resolved fluoroimmunoassay of IgG4 based on magnetic microspheres.

BACKGROUND: The abnormal increase in serum IgG4 level is an important clinical symptom of IgG4-related disease (IgG4-RD), and the detection of serum IgG4 level is a powerful tool for the diagnosis of IgG4-RD. This study was conducted to establish a simple and rapid immunoassay for the determination of human serum IgG4 levels. METHODS: Based on the competition method, a novel immunoassay was established for the determination of human serum IgG4 using a combination of time-resolved fluoroimmunoassay (TRFIA) and magnetic microspheres. IgG4 was coupled with magnetic microspheres and competed with IgG4 in the samples to bind the Eu3+ -labeled anti-IgG4 antibody. The immunocomplex was separated and washed in a magnetic field, and the fluorescence counts were measured according to the number of dissociated europium ions. RESULTS: The analytical sensitivity of IgG4-TRFIA based on magnetic microspheres was 0.006 g/L, and the detection range was 0.006-20 g/L under optimal conditions. The precision, recovery, and specificity of this immunoassay were demonstrated to be acceptable. The clinical application of IgG4-TRFIA based on magnetic microspheres was evaluated and compared with that of immunonephelometry. The results showed that the two detection methods had a good correlation, with a correlation coefficient of .9871. CONCLUSION: IgG4-TRFIA based on magnetic microspheres has the advantages of high sensitivity, wide detection range, and short analysis time and has the potential to become a useful tool for the diagnosis of IgG4-RD.

Evaluation of Noninvasive Hemoglobin Measurements in Trauma Patients: A Repeat Study.

INTRODUCTION: Reliable, accurate, and non-invasive hemoglobin measurements would be useful in the trauma setting. The aim of this study was to re-examine the ability of the Masimo Radical 7 in this setting after recent hardware and software improvements. METHODS: Level 1 Trauma patients were prospectively enrolled in the study over a 9-mo period with the goal of obtaining 3 paired data points from 150 patients admitted to the ICU or IMU. Hospital laboratory hemoglobin values were compared with cyanomethemoglobin (HiCN) and Masimo device hemoglobin (SpHb) values using comparison plots and Bland-Altman analysis. RESULTS: A total of 380 patients were enrolled in the study with 150 of those being admitted to the ICU or IMU. Comparison of hospital lab hemoglobin and HiCN (n = 494) found a correlation of R2 = 0.92. Comparison of hospital lab hemoglobin and Masimo device hemoglobin (n = 218) found a correlation of R2 = 0.27. Bland-Altman analysis of the 218 of the comparable hospital hemoglobin and Masimo device hemoglobin values had a bias of 0.505 g/dL with 95% of values within the limits of agreement of 4.06 g/dL to -3.60 g/dL. CONCLUSIONS: The Masimo Radical 7 device has the potential to provide timely, useful clinical information, but it is not currently able to serve as an initial noninvasive diagnostic tool for trauma patients. There was poor correlation between clinical Hgb and SpHb, and because of that, SpHb should not be used to evaluate hemoglobin levels in trauma patients.

Prehospital coagulation measurement by a portable blood analyzer in a helicopter emergency medical service (HEMS).

In helicopter emergency medical services, HEMS, coagulopathy presents both in trauma (e.g. consumption of coagulation factors) and non-trauma cases (e.g. anticoagulant use). Therefore, in HEMS coagulation measurements appear promising and Prothrombin Time (PT) and derived INR are attractive variables herein. We tested the feasibility of prehospital PT/INR coagulation measurements in HEMS. This study was performed at the Dutch HEMS, using a portable blood analyzer (i-Stat®1, Abbott). PT/INR measurements were performed on (hemodiluted) author's blood, and both trauma- and non-trauma HEMS patients. Device-related benefits of the i-Stat PT/INR system were portability, speed and ease of handling. Limitations included a rather narrow operational temperature range (16-30 °C). PT/INR measurements (n = 15) were performed on hemodiluted blood, and both trauma and non-trauma patients. The PT/INR results confirmed effects of hemodilution and anticoagulation, however, most measurement results were in the normal INR-range (0.9-1.2). We conclude that prehospital PT/INR measurements, although with limitations, are feasible in HEMS operations.

Rapid Characterization of Drugs in Biological Fluid and Seized Material Using Thermal-Assisted Carbon Fiber Ionization Mass Spectrometry.

Developing a rapid, simple, and sensitive method to analyze drugs is critical to forensic research study because of the widespread occurrence of the matrix effect. Herein, we develop a method using thermal-assisted carbon fiber ionization mass spectrometry that can be used to directly analyze drugs in biological fluid. The key feature of this technique is that the biological samples such as urine and blood can be achieved online as precipitated protein on the carbon fiber tip and thermally desorbed by the metal ceramics heater, which can reduce the matrix effects and improve the sensitivity. Analytes including raw urine, blood, oral fluid, drink, tobacco tar, drug tablets, and paper cards can be rapidly identified and analyzed within a few minutes regardless of their physical variations. Due to its simplicity and noninvasive analysis, this method can be used for drugged driving analysis and to achieve point-of-care drug testing in clinical and forensic chemistry.

Plasma or serum, which is the better choice for the measurement of metanephrines?

Measurement of metanephrines (MNs: metanephrine [MN] and normetanephrine [NMN]) is recommended for the initial biochemical diagnosis of pheochromocytoma and paraganglioma. Despite some drawbacks, plasma is commonly used for sampling. Here, we determined the feasibility of using serum, as an alternative to plasma, by comparing MNs in plasma and serum and evaluating the stability of MNs in serum. MNs obtained from serum, EDTA plasma, and heparin plasma were measured using LC-MS/MS immediately or after storage at 4 °C for 24 h, 72 h, and 7 days, and at -80 °C for 7 days, after sample collection. The differences between sample stability at given time points were compared using one-way ANOVA and Students' paired t-test, and the mean percent deviation was compared with total change limit (TCL). No significant difference was observed in MN and NMN between serum and EDTA plasma, and the mean percent deviation of the results obtained from serum compared to that from EDTA plasma was within the TCL. However, the difference of MN between EDTA plasma and heparin plasma exceeded the TCL. Both MNs in EDTA plasma and heparin plasma showed a significant decreasing trend at 4 °C with time (p < .01), while those in serum were relatively stable, with the mean percent deviation not exceeding the TCL at any time point or temperature. In conclusion, MNs measurement did not significantly differ between EDTA plasma and serum when measured immediately after collection, and MNs in serum were more stable than that in plasma.

Development of a designated comparison method for alkaline phosphatase measurements and its application to evaluating routine methods.

The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) published the reference measurement procedure (RMP) for ALP measurement in 2011. However, the RMP is of high requirements for laboratories, complicated, time-consuming and high cost of reagents. Many manufacturers do not trace results to the higher procedure. And there is currently no designated comparison method (DCM) for ALP measurement. Thus, the standardization of ALP measurement is hindered. Automatic biochemical analyzers are easy to operate and widely used in clinical laboratories. Therefore, according to the RMP, establishing a DCM based on an automatic biochemical analyzer will be a practical way to establish traceability to the accuracy base and promote the standardization of ALP measurement. On the basis of conforming to the RMP recommended by IFCC as far as possible, the DCM was established based on a Thermo Indiko automatic biochemical analyzer. Performances of the method were validated. The DCM repeatability and within laboratory imprecision was <1% and <2.5%, respectively. For evaluation of trueness, the biases were within the equivalent limits. Measurement procedure comparisons and biases estimation were carried out between the DCM, the RMP, and the six routine methods using a panel of 40 individual human serum samples. The comparisons between the DCM and the RMP gave satisfying results. Compared with the DCM, the relative biases of some routine methods failed to meet the bias limit derived from biological variation.

The use of whole blood capillary samples to measure 15 analytes for a home-collect biochemistry service during the SARS-CoV-2 pandemic: A proposed model from North West London Pathology.

BACKGROUND: The COVID-19 pandemic has drastically changed the delivery of secondary care services. Self-collection of capillary blood at home can facilitate the monitoring of patients with chronic disease to support virtual clinics while mitigating the risk of SARS-CoV-2 infection and transmission. OBJECTIVE: To investigate the comparability of whole blood capillary and plasma venous samples for 15 routinely used biochemical analytes and to develop and pilot a user-friendly home-collection kit to support virtual outpatient clinical services. METHODS: To investigate the comparability of whole blood capillary and plasma venous samples for 15 routinely requested biochemical analytes, simultaneous samples of venous and capillary blood were collected in EDTA and lithium-heparin plasma separation tubes that were of 4-6 mL and 400-600 µL draw volume, respectively. Venous samples were analysed within 4 h of collection while capillary samples were kept at ambient temperature for three days until centrifugation and analysis. Analyte results that were comparable between the matrices were then piloted in a feasibility study in three outpatient clinical services. RESULTS: HbA1c, lipid profile and liver function tests were considered comparable and piloted in the patient feasibility study. The home-collect kit demonstrated good patient usability. CONCLUSION: Home collection of capillary blood could be a clinically-useful tool to deliver virtual care to patients with chronic disease.

Use of a Portable Analyzer for Venous Blood Gas and Biochemistry Analysis in Free-Ranging Indian Flying Foxes (Pteropus giganteus) in Myanmar.

We determined venous blood gas, acid-base, and biochemical parameters for thirteen free-ranging Indian flying foxes (Pteropus giganteus) in Myanmar, using a handheld i-STAT analyzer with CG8+ and CHEM8 cartridges. For field-based projects, portable blood analyzers enable identification and management of electrolyte and acid-base imbalances and collection of physiologic data, but present logistical challenges.

Temperature and Concentration Dependence of Human Whole Blood and Protein Drying Droplets.

The drying of bio-colloidal droplets can be used in many medical and forensic applications. The whole human blood is the most complex bio-colloid system, whereas bovine serum albumin (BSA) is the simplest. This paper focuses on the drying characteristics and the final morphology of these two bio-colloids. The experiments were conducted by varying their initial concentrations, and the solutions were dried under various controlled substrate temperatures using optical and scanning electron microscopy. The droplet parameters (the contact angle, the fluid front, and the first-order image statistics) reveal the drying process's unique features. Interestingly, both BSA and blood drying droplets' contact angle measurements show evidence of a concentration-driven transition as the behavior changes from non-monotonic to monotonic decrease. This result indicates that this transition behavior is not limited to multi-component bio-colloid (blood) only, but may be a phenomenon of a bio-colloidal solution containing a large number of interacting components. The high dilution of blood behaves like the BSA solution. The ring-like deposition, the crack morphology, and the microstructures suggest that the components have enough time to segregate and deposit onto the substrate under ambient conditions. However, there is insufficient time for evaporative-driven segregation to occur at elevated temperatures, as expected.