bluuebunny/crossref_metadata_2025 huggingface dataset:
A-294 Exocytosis Inhibitor Increases yield of Limulus Amebocyte Lysate (LAL), Used for adjunct diagnosis of Invasive Fungal infection
Authors: Zhang M , Zhang S , Zhang J
Published: October 2024

Background

The limulus amebocyte lysate (LAL) was widely used in endotoxin detection in vitro and the clinical diagnosis of invasive fungal infection. The previous data showed that a caffeine collection solution could prevent degranulation during the blood collection procedure, and caffeine-derived LAL could work in both the chromogenic test and turbidimetric method assays. However, the cell pellets collected by caffeine collection solution aggregates after re-suspension in 5 mM CaCl2. No similar phenomenon was observed with PBS collection buffer. The purpose of this study is to set up a PBS-caffeine bleed solution to improve the yield of LAL

Methods

During the 2023 bleed season, experiments were carried out to test the results of PBS-caffeine solution on the degranulation during bleed process. 6 crabs were bled once a week for a total of 60 crabs by the PBS-caffeine collection solution. The blood of each crab was collected by PBS caffeine collection solution. The cell pellets were finally re-suspended into 5 mM CaCl2 to promote degranulation. The LAL activity was tested by both chromogenic and turbidimetric assay methods.

Results

The data demonstrates that PBS-caffeine collection solution could prevent degranulation for over 4 hours, and the activity yield of PBS-caffeine-derived LAL was higher. There was no discernable impact on the activity yield of the crab’s size during the bleed season. PBS-caffeine-collection solution could reduce amebocyte aggregation/clot formation during processing. Studies described the biochemical characteristics of PBS-caffeine-derived LAL. Moreover, PBS-caffeine-derived LAL could work in both the chromogenic and turbidimetric assays.

Conclusions

First, PBS-caffeine collection solutions prevent amebocyte degranulation during blood collection and processing. Next, a PBS-caffeine collection solution could reduce cell aggregation/clotting during processing, and the activity of PBS-caffeine LAL is higher. Finally, PBS LAL is functional in both the chromogenic test and turbidimetric assays
A-295 New Transport Media to Preserve Viable Parasites, Bacteria and Fungus
Authors: Ordonez-Smith M E
Published: October 2024

Background

Patients with various infections not always show positive results in their cultures. Therefore, the purpose of this study is to show that a transport media is needed to preserve bacteria, parasites and fungi, which can help patients when collecting samples to determine their infections, the most common urine or feces. The microorganisms can be kept immediately in the transport media when they are taken by the patient and the first step is very important to keep them alive. The preanalytical step is essential for a good diagnostic and accurately determines their etiology.

Methods

The transport media that I am referring to, was designed by our laboratory. It is a tube with an enriched broth, it can be kept at room temperature for a year. To show that this transport media can be trusted, different samples were tested such as: Urine, semen, wounds, eye secretions and feces were tested at different temperatures: refrigerator 2°C, environment 18°C and in a “kangaroo” corporal temperature or an incubator at 37°C. Also, times were tested between the collection and transport to the laboratory to be proceeded. To have a good diagnostic the sample should be smeared onto the transport media and kept there at least two or more hours at normal corporal temperature. There is no problem to send the tube at room temperature to the laboratory. All samples were smeared for bacterias in MacConkey agar, EMB (Eosin Methylene Blue) agar, CLED (Cystine-Lactose-Electrolyte Deficient) agar with Andrade Indicator, Blood agar, Chocolate agar, XLD agar. For fungi in Potato or Sabouraud agar. The parasites were studied in saline solution and parasitological lugol.

Results

The samples most studied were 1600 samples of feces, 700 urines and 100 other samples, such as genital, eye secretions, wounds. The percentage of positive etiology with this transport media was 67.9% of fungi versus 73.5% without the transport media. The aerobic bacteria and helminths eggs or adults can be in this transport media for many days, there is no difference and Giardia lamblia trophozoites can be kept as long as seven hours.

Conclusions

Nowadays, there are various commercial transport media for each microorganism. The great advantage of our transport media is used for three etiologies: Bacteria, parasites and fungi, plus can be kept at room temperature for several days. It is very easy to used, the tube of the transport media can be placed in a “kangaroo” style to keep the samples at corporal temperature. It is helpful in case the patient lives far away or takes the sample at night. The transport media can keep the samples at 37°C at all time at corporal temperature. This new transport media is essential to obtain accurate positive cultures and can give a better diagnostic, since the microorganisms are alive. Knowing the etiology, the treatment is accurate and the patient´s health is always necessary.
A-300 Comparative Analysis of Serology Test Performance: Evaluation of Elecsys Platform for Hepatitis Markers
Authors: Metushi I , Kim S , Javier G , Ciobanu D , Nunez G , Jurie R , Drake T A , Garner O
Published: October 2024

Background

Serology tests that target markers such as: anti-hepatitis A IgM virus (anti-HAV IgM), anti-HAV total antibody, anti-hepatitis B core IgM (anti-HBc IgM), anti-HBc total, anti-HB surface (anti-HBs), HBs antigen and anti-hepatitis C virus (anti-HCV) total play a pivotal role in understanding the stage of infection, immunity and vaccination effectiveness. Here, we evaluated these markers on our new total laboratory automation line that uses the Roche Elecsys platform.

Methods

The existing reference method used was the Siemens Centaur. Precision was evaluated by running a negative and a positive sample a minimum of 25 times. Method comparison was performed by using human samples with negative and positive values as outlined in Table 1 below. Analysis was performed by EP Evaluator.

Results

Samples for precision were 100 % concordant. Method comparison for each test yielded the results outlined in Table 1. Tests such as anti-HBs and HBsAg had 100% agreement between the two methods. Anti-HAV total had only one sample classified as positive by Elecsys that was negative by the reference (Centaur), resulting in 99% overall agreement. Anti-HAV IgM had had 4 results positive by Centaur that were negative by Elecsys. Upon further investigation, of the four samples, one was confirmed to be a true negative by chart review, two samples were run on the Abbott platform and were confirmed to be negative matching Elecsys. Anti-HBc IgM had 54% positive agreement and 100% negative agreement with Elecsys giving 6 discordant samples. These results were evaluated by clinical review and ruled to be true negative. Anti-HBc total and anti-HCV total had 99% and 96% overall agreement respectively.

Conclusions

We conclude that the Roche Elecsys platform for infectious serology tests is precise and accurate to be used in the clinical laboratory.
A-302 Evaluation of real-time PCR assays for detection of sexually-transmitted infections
Authors: Soong H
Published: October 2024

Background

Sexually transmitted infections (STIs) have serious negative consequences for reproductive health worldwide. They are associated with infertility, premature birth and neonatal infections. Five STI pathogens, namely Trichomonas vaginalis, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum were selected for the evaluation of three potential real-time PCR assays that can be adopted for diagnostic testing.

Methods

A total of 36 samples were included, consisting of genital swabs, urine, abscesses and samples provided by quality assurance programmes. DNA extraction was performed using an automated nucleic acid extraction system, abGenixTM. Commercial genomic controls and DNA extracts donated by external laboratories were used as well. The extracted nucleic acids were tested using three different assays, namely Seegene Anyplex II STI-5 Detection, Thermo Fisher Scientific customized STI Panel assay, and TIB MOLBIOL STI LightMix Modular kits, according to the manufacturers’ instructions.

Results

A total of 67% and 11% of the samples showed equivalent positive and negative results, respectively. However, 22% of the samples had non-concordant results. TIB MOLBIOL STI LightMix Modular kit was unable to differentiate between Ureaplasma parvum and Ureaplasma urealyticum in 9 samples. Genomic controls were tested, and Seegene Anyplex II STI-5 Detection was unable to detect lower concentrations of DNA for Trichomonas vaginalis, Mycoplasma genitalium and Mycoplasma hominis. All assays were able to detect lower concentrations of Ureaplasma parvum DNA, but detectable concentrations were higher for Ureaplasma urealyticum.

Conclusions

In conclusion, the performance of each assay differed according to pathogen. None of the assays offered equal performance for all pathogens. We have adopted Thermo Fisher Scientific customized STI Panel assay in our diagnostic testing due to its advantage of being user friendly and cost effective.
A-308 Placental Growth Factor Kryptor Immunoassay Reveals Quality Control Imprecision and Drift
Authors: Chan C , Chen G , Schaefer R F , Echevarria F J , Yeo K J
Published: October 2024

Background

The utility and value of determining the soluble fms-like tyrosine kinase-1 to placental growth factor (sFlt-1/PlGF) ratio for predicting the likelihood of progression to pre-eclampsia in pregnant women admitted with hypertension are increasingly becoming widely recognized. A key finding of the multi-center PRAECIS trial (NEJM Evid 2022;1(12)) is the observation that sFlt-1/PlGF ratios ≥ 40 correlate with higher risk for adverse maternal outcomes. The sFlt-1 and PlGF immunoassays performed on the ThermoFisher Scientific B·R·A·H·M·S Kryptor autoanalyzer became the first FDA-approved tests in 2023 for determining sFlt-1/PlGF ratio. In this study, an evaluation of the analytical performance of the sFlt-1 and PlGF KRYPTOR immunoassays was performed, which included analyte measuring range (AMR), accuracy, precision, and stability studies.

Methods

Calibration and QC materials (consisting of lyophilized recombinant human proteins), test reagents and solutions, and consumables were purchased and provided by ThermoFisher Scientific. Analytical runs were performed according to vendor’s instructions by trained medical laboratory scientists. Between-day precision of our two instruments for both immunoassays was assessed by assaying all three levels of sFlt-1 and PlGF QC materials, as well as patient serum pools with low PlGF concentration, once to twice daily for multiple consecutive days.

Results

While the analytical performance of the sFlt-1 immunoassay was robust and performed according to expectation (within-day CV <1% and between-day CV <3%), the PlGF immunoassay was surprisingly less reliable. Imprecision and inaccuracy of the PlGF immunoassay at the low end of its analytical measurement range was reflected by both sporadically out-of-control between-day measurements of all three QC levels (with target ranges of 24 - 36 pg/mL, 80 - 120 pg/mL, and 320 - 480 pg/mL), as well as slow downward drifts of particularly the low level QC material. In one instance, a downtrend was observed from 28 pg/mL to 14 pg/mL over 6 days, even with fresh reagents, solutions, and calibration. Such shortened stability of the PlGF assay does not meet the vendor’s claims of calibration stability of 15 days and onboard kit stability of 29 days. Using vendor’s provided material, the AMR of both sFlt-1 and PlGF were adequately verified and showed excellent linearity (r2> 0.99).

Conclusions

Despite low level QC imprecision and drift, the sFlt-1/PlGF ratios determined using the B·R·A·H·M·S Kryptor analyzers are acceptable for clinical use but with the caveat that we will perform batch testing with bracketing QCs and conduct stringent QC monitoring, frequent calibrations, and reduce the onboard kit stability as defined by ThermoFisher Scientific. Our findings serve as a reminder that FDA approval does not preclude thorough verification studies of any assay prior to implementation for clinical use.
A-319 Capillary Blood Collection for Egg-cellent Reproductive Insights
Authors: Brandon W C , Collier B B , Chappell M R , Iacovetti G , Peevler M , Schaff U Y , Sommer G J , Grant R P
Published: October 2024

Background

In the United States, an estimated 13% of women between the ages of 15 and 49 years, experience impaired reproductive potential (fecundity). Assessment of fecundity typically requires an in-person physician visit and venous blood collection to evaluate hormone levels and identify potential reproductive health conditions. Exploring less invasive, at-home sampling options could offer couples insights into their personal reproductive abilities, providing peace of mind and aiding in family planning.

Methods

Capillary blood, obtained using the Tasso®+ capillary blood collection device coupled with a BD Microtainer® serum tube, was utilized for measurements of analytes associated with female fecundity (follicle stimulating hormone, luteinizing hormone, estradiol, progesterone, anti-Müllerian hormone, and prolactin). These are all FDA-approved assays measured on Roche cobas® e801, assay parameters remained unchanged. Professional and self-collected capillary serum samples were acquired in parallel with the standard venous serum samples, to compare clinical equivalency of the capillary sampling option. In addition to isothermal stability studies at room temperature (20-25°C) and refrigerated (2-8°C) conditions, shipping excursion studies based on ISTA 7D recommendations were performed using a novel packaging solution to control sample temperature and thus, specimen integrity. Studies to assess matrix equivalency, linearity, and imprecision of this alternate sample type were also performed to demonstrate analytical performance.

Results

Method comparison of venous and professional collection of capillary samples demonstrated correlations (R) ≥ 0.9720 with slopes ranging from 0.919 to 0.971 and mean biases within ±8.2% for all analytes (n = 19-79). Self-collected capillary serum samples demonstrated correlations (R) ≥ 0.9827 with slopes that ranged from 0.841 to 0.985 and mean biases within ±10.7% (n = 16-26). Isothermal stability was demonstrated for each analyte up to 7 days at room temperature and refrigerated conditions. Simulated shipping excursion results were found to be acceptable for both winter and summer conditions with mean biases for each analyte within ±10.2% and ±19.2%, respectively. Matrix equivalency, linearity, and imprecision results adhered to current CLIA acceptance limits for each respective measurement.

Conclusions

The analytical and stability results affirm the feasibility of collecting capillary serum in a patient-centric manner, providing women with relevant information about their reproductive health.
A-328 Accuracy of the Glucose Test in the i-STAT® G Cartridge Using the i-STAT 1 System for Venous, Arterial and Capillary Whole Blood Specimens in Clinical Settings
Authors: Kornfeld S F , Gonzalez Aguirre M , Zhang H , Hahn S
Published: October 2024

Background

Precise and accurate measurements of whole blood glucose levels are important for the diagnosis, monitoring and treatment of carbohydrate metabolism disorders, such as diabetes and hypoglycemia. This study demonstrates the accuracy of the glucose test in the i-STAT G cartridge with the i-STAT 1 System in arterial, venous, and capillary whole blood specimens in point of care or clinical laboratory settings.

Methods

The accuracy of the glucose test in the i-STAT G cartridge was assessed at external clinical sites in a method comparison study using whole blood specimens across the measurement range of 20 - 700 mg/dL. Specimens used in this study were venous, arterial, and capillary specimens prospectively collected under Institutional Review Board-approved informed consent or were leftover de-identified venous or arterial specimens. The study included venous whole blood samples from 164 adult subjects (≥ 18 years) and arterial whole blood samples from 173 adult subjects at 3 clinical sites, and capillary whole blood samples from 211 adult subject at 3 clinicals sites and 23 neonate subjects (birth to 28 days) at 2 clinical sites.

For venous and arterial whole blood, samples were collected and tested in duplicate on the i-STAT G cartridge and on the i-STAT CHEM8+ cartridge (comparator). For capillary whole blood samples, adult fingerstick samples and neonate heel-stick samples were collected in capillary tubes and tested in singlicate on the i-STAT G cartridge and in singlicate on the epoc® Blood Analysis System (comparator). Passing-Bablok linear regression was performed for venous and arterial whole blood samples using the first replicate from the i-STAT G cartridge versus the mean result of the comparator, and for capillary whole blood samples (adult and neonate combined) using the singlicate result from the i-STAT G cartridge versus the singlicate result of the comparator.

Results

Passing-Bablok regression of i-STAT G cartridge results versus the comparator was used to calculate slope and correlation coefficient (r). Adult venous whole blood results had slope = 1.00 and r = 1.00, and adult arterial whole blood results had slope = 1.00 and r = 1.00. Adult and neonate capillary whole blood results had slope = 1.00 and r = 1.00.

Conclusions

These results demonstrate that the i-STAT 1 System delivers accurate glucose test results within ∼2 minutes using the i-STAT G cartridge for venous, arterial and capillary whole blood samples for adult and neonate subjects across a glucose range of 20-700 mg/dL when tested by end-users in a point of care or clinical laboratory setting.

This study was funded by Abbott Laboratories.
A-337 The Utility of Urinary Human Chorionic Gonadotropin Testing in the Emergency Department
Authors: Kim R , Altura M , Smith K , Hashim I
Published: October 2024

Background

Human chorionic gonadotropin (hCG) levels are measured in both urine and blood as an indication of suspected pregnancy, and assessment of progress of conception. It is also measured in the investigation of patients presenting with acute abdomen and suspected of ectopic or molar pregnancy. This study reviewed the utility of urine pregnancy test in a large university teaching hospital.

Methods

Results of all urinary hCG tests (using hCG Combo Pregnancy kit, MEDLINE, IL) performed as point of care in the emergency department during the year 2023 were obtained. Corresponding plasma hcG levels performed (Total β-HCG Alinity immunoassay, Abbott Diagnostics, IL) were also obtained. Analysis of hCG testing outcomes were assessed.

Results

A total of 2848 urinary hCG tests were performed during the study period. The majority 2113 (74.2%) of samples were negative for hCG whereas 835 samples (29.3) were positive. Among the positive hCG urine samples, 401 patients (48%) had plasma hCG requested and performed. Plasma hCG values ranged from < 2.4 (26.5) to 219,462.5 mIU/mL (median 16,872.35 mIU/mL). One plasma sample with corresponding positive urinary hCG result had plasma hCG level <2.4 mIU/mL which is below the detection limit of the assay suggesting a false positive urinary hCG result. Among the 13 patients with serial plasma hCG values, only one patient exhibited doubling (48 hours) hCG values when less than 13,000 mIU/mL. One patient had a declining serial hCG plasma values suggesting failing conception. The remaining patients with consecutive plasma hCG values cannot be assessed as either the time gap was excessive or hCG values were markedly elevated (> 30,000 mIU/mL).

Conclusions

Although the utility of urinary hCG testing in the emergency department appeared appropriate, unnecessary repeat analysis with appropriate plasma request represented 3.2%. An electronic test request duplicate notification may help resolve this unnecessary repeat.
A-343 Novel In-Line Hemolysis Detection on a Blood Gas Analyzer for Capillary Samples
Authors: Adib L , Butler M , McNary N , Balasubramanian S , Pamidi P
Published: October 2024

Background

Point-of-care (POC) blood gas and electrolyte analyzers utilizing whole blood as the predominant sample type are blinded by the presence of hemolysis until today. Moreover, capillary samples are particularly vulnerable to in-vitro hemolysis due to excessive force applied during sample collection. Here, we introduce the GEM Premier 7000 with iQM3 (GEM 7000) which incorporates automatic, in-line hemolysis detection in capillary blood gas samples without a need for additional sample volume or reagents.

Methods

The hemolysis detection module which is integrated into the disposable GEM cartridge uses acoustophoretic technology and photometric measurements to detect hemolysis in whole blood. In GEM 7000, hemolysis of ≥ 116 mg/dL was found to have significant interference with potassium results. A hemolysis flag is presented as the degree of hemolysis: none (0 - 50 and 51 - 115), mild (116 - 200 and 201 - 300), moderate (301 - 400), and gross (≥401). Due to volume limitations with native capillary samples and challenges in assessing hemolysis levels with a comparator assay, venous blood spiked volumetrically with hemolysate and transferred to capillary devices was used to verify the hemolysis flag performance. An agreement analysis was performed using the Roche cobas hemolysis value. The device's (GEM 7000) ability to flag hemolyzed capillary samples is demonstrated in a simulated clinical setting using native and contrived fingerstick capillary samples.

Results

Hemolysis verification with transferred capillary samples demonstrated that 98.2% (274/279) of samples were correctly flagged based on the cobas hemolysis value of spiked hemoglobin. Hemolysis in the native capillary samples (N = 235) was primarily distributed in the 0-50 mg/dL range. Additionally, native capillary samples altered using vigorous flea mixing (> 1 minute) showed hemolysis distribution over a wide hemolysis degree (none to gross), and their potassium results were flagged accordingly.

Conclusions

By providing integrated hemolysis detection in capillary blood sample measurements, the GEM Premier 7000 with iQM3 system can provide quality and confidence in the clinical interpretation of critical results such as potassium.
A-351 Versatile and Sensitive Microfluidic Immunoassay for Improved Point-of-Care Diagnostics
Authors: Bennett S J , Link J S , Dolence A , Call Z D , Martinez B , Henry C S
Published: October 2024

Background

Healthcare professionals must choose between sensitivity and ease-of-use in diagnostics, particularly for diseases like COVID-19 and strep throat. Traditional enzyme-linked immunosorbent assays (ELISAs) are sensitive but are manually intensive and lengthy. Lateral flow assays (LFAs) are an alternative with low cost, ease-of-use, and rapid results; but LFAs suffer from low sensitivity. Burst Diagnostics presents a groundbreaking solution with the capillary-driven immunoassay (CaDI), a novel microfluidic device delivering sensitivity comparable to ELISA with the ease of LFAs.

Methods

The CaDI is made of flow channels defined by layered transparency and adhesive sheets containing reagent pads with HRP-conjugated antibody and luminol. The system requires only a sample addition step by the user. Sample flow initiates sequential steps of a sandwich ELISA, fully automated by the device, to provide a chemiluminescent signal in 10 minutes or less, depending on sample matrix.

Results

We have demonstrated success with preliminary studies for the detection of SARS-CoV-2 nucleocapsid protein (NP) and group A streptococcus (GAS). Detection of NP was achieved by assembling and optimizing COVID-19 CaDI’s using anti-NP antibodies. Then, spiked nasal swab samples were tested ranging from 10 to 1000 PFU/mL with positive detection as low as 10 PFU/mL, much less than the same samples in a traditional LFA (see figure). Additionally, we have demonstrated successful detection of GAS in optimized buffer conditions up to 100-fold less than commonly used LFAs. Finally, multiplexed CaDI’s increase throughput and cost-effectiveness in the point-of-care setting.

Conclusions

The CaDI platform bridges the ease of LFAs and sensitivity/specificity of laboratory tests. Currently, the CaDI can detect SARS-CoV-2 NP and GAS with higher sensitivity than existing LFAs. Development is underway for a reader to accompany the CaDI and further simplify the test. Importantly, the potential targets for detection are immense due to the sensitivity, simplicity, and adaptability of the platform.
A-355 Comparison of Arterial and Venous Whole Blood Samples Analyzed on the QuantraSystem With the QPlusand QStatCartridges
Authors: Uribe A A , Flores A , Fiorda-Diaz J , Vera-Miquilena E , Reeves J , Applegate B , Waldron A , Oldendorp G , Viola F , Winegar D
Published: October 2024

Background

The Quantra Hemostasis System (HemoSonics, LLC) is a cartridge-based viscoelastic testing system used to monitor the coagulation status of whole blood samples. The clinical performance of the System with the QPlus and QStat Cartridges was demonstrated in patients undergoing surgical procedures using venous blood samples. However, depending on the nature of the surgical procedure, arterial or venous samples may be more accessible for testing. It is currently unknown if differences exist between the two samples for the Quantra System. This study compared QPlus and QStat parameters measurements in venous and arterial blood samples collected in parallel from patients undergoing cardiac or liver transplant surgery.

Methods

Two studies were conducted according to CLSI EP09. The cardiac study enrolled 50 adult patients undergoing cardiac surgery utilizing cardiopulmonary bypass to evaluate QPlus parameters. Matching arterial and venous samples were obtained at two time points: during bypass and post-protamine. The liver study enrolled 25 adult patients undergoing liver transplantation to evaluate QStat parameters. Matching arterial and venous samples from were obtained at three time points: baseline, anhepatic and reperfusion phases. All arterial samples were drawn from an existing arterial catheter whereas venous samples were drawn from the venous side of the bypass circuit or from the central venous catheter (proximal port to minimize infusion contamination). Linear regression analysis and means comparison (paired t-test) were used to assess whether the two sample types provided equivalent results,

Results

Table 1 provides the mean values for each parameter determined for venous and arterial samples. None of the parameters showed a significant difference between sample types (P > 0.05). Additionally, the linear regression analysis show strong correlation between the results for each parameter.

Conclusions

Both studies demonstrated that venous and arterial whole blood samples provide equivalent results on the Quantra System with the QPlus and QStat Cartridges.
A-358 Extended linearity studies for pO2, pCO2, K+ Cl- on GEM 5000 blood gas analyzers using a combination of verification materials
Authors: Samara Simha Subhash Chandra V , Khatoon H , Yeo K J
Published: October 2024

Background

Blood gas analyzers (BGA) measure blood gases pO2,pCO2,O2Hb,COHb,MetHb, and several analytes in the workup and management of acid-base disorders. GEM 5000 BGA (Instrumentation Laboratory, a Werfen Company) have very broad reportable ranges for the measured analytes. However, manufacturer’s current linearity materials do not cover the entire reportable ranges claims. This poses challenge to clinical laboratories, especially for pO2 and pCO2 to comply with College of American Pathologists (CAP) requirements to verify instruments performance every six months through the entire reportable range. We evaluated secondary materials in combination with manufacturer’s primary linearity materials for pO2, pCO2, K+ and Cl- for an extended linearity verification.

Methods

Routine linearity studies was performed with PVP (5-levels), a primary material provided by the GEM 5000 analyzer manufacturer. Hypoxic (pO2: 5-25mmHg) and hyperbaric (pO2: 600-670mmHg) materials obtained from Eurotrol Inc. and VK-R5 linearity material (Radiometer America Inc.) for pCO2, K+ and Cl- were processed on GEM 5000. All materials at all levels were assayed in duplicate. Results from PVP, Eurotrol and VK-R5 were combined from low to high levels to assess linearity verification.

Results

Linearity range of 15-630mmHg with r2=0.99 was verified for pO2. Using a combination of VK-R5 with PVP, a linearity range of 14-127 mmHg (r2=0.99) for pCO2, 1.1-14.1 mmol/L (r2=1.00) for K+, and 51-153 mmol/L (r2=1.00) for Cl-were verified. See table for details.

Conclusions

A combination of BGA manufacturer’s primary linearity material with secondary vendors material was useful in addressing linearity verification for blood gases pO2, pCO2, and electrolytes K+Cl- over an extended range close to the manufacturer’s claims. We recommend other laboratories that experience similar BGA linearity verification challenges to consider this approach for verification of the manufacturer’s claims. It would have been very helpful if manufacturer can provide materials that cover both the lower and upper limits of their claims.
A-359 Clinical Performance Evaluation of the Polymerase Chain Reaction (PCR)-Based cobas CT/NG/MG Test for Use on the cobas liat System in a Clinical Laboratory Setting and Point-of-Care (POC) Location
Authors: Van Der Pol B , Arcenas R , Boraas C , Chavoustie S , Crane L L , d'Empaire N , Ermel A C , Harnett G , Hinestrosa F , House S , Lillis R , Miller J , Mills A , Poblete R , Young S A
Published: October 2024

Background

Screening for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Mycoplasma genitalium (MG) can be achieved rapidly (in approximately 20 minutes) with the cobas® CT/NG/MG test (assay not cleared by US FDA. Submission currently under review and subject to change per health authority feedback). This automated, qualitative, real-time PCR-based nucleic acid amplification test (NAAT) is for use on the cobas® liat® system. This study evaluated the test’s clinical performance using urogenital samples from symptomatic and asymptomatic patients.

Methods

This non-interventional, non-observational study used prospective clinician-collected and self-collected specimens (urine, and vaginal swabs, all in cobas® PCR Media) from symptomatic/asymptomatic patients ≥14 years old from 13 POC sites across the US. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of cobas liat CT/NG/MG were calculated with respect to patient infected status (PIS), as determined using results from three FDA-approved NAATs and one laboratory-developed test. Due to insufficient positive NG samples during the trial period, further testing used archived samples.

Results

The median (range) age of the study population (N=4,800) was 35.0 (15.0-81.0) years; 40.4% (n=1,941) were symptomatic and 51.9% (n=2,489) were assigned female at birth. The cobas CT/NG/MG nucleic acid test demonstrated good clinical performance (Table 1). Across all specimen types, specificity was >97% for each analyte. Sensitivity was ≥95%, except in female urine (CT 87.0%, NG 93.1%, MG 78.9%). Regardless of specimen type, PPV and NPV were ≥95% for CT and NG; PPV for MG was highest in male urine (92.7%) and NPV was >97.5% across analytes.

Conclusions

In a clinical setting, the cobas CT/NG/MG nucleic acid test showed good clinical performance for the detection of CT, NG, and MG in urogenital samples, in addition to providing a short turn-around time and centralized testing lab quality at the POC for both self- and clinician-collected samples.
A-362 Hemolysis Detection and Flagging of Potassium Results on GEM Premier 7000 with iQM3
Authors: Butler M , Adib L , McNary N , Balasubramanian S , Pamidi P
Published: October 2024

Background

Blood gas analyzers that report whole blood potassium (K+) are vulnerable to inaccurate results due to in vitro hemolysis. GEM Premier 7000 with iQM3 (GEM 7000) automatically detects hemolysis (plasma free hemoglobin) and flags impacted K+ results. Here, we report the hemolysis impact on K+ measurements and the flagging approach used in the GEM 7000 system.

Methods

Hemolysis interference was assessed according to CLSI EP07c at low (3.8 mmol/L) and high (5.3 mmol/L) K+ levels. Ultrasonically-lysed whole blood was used to generate a high test pool (100% = 1000 mg/dL hemoglobin). This was mixed volumetrically with a low pool (0% = native blood) to create additional test pools (25%, 50%, and 75%) and analyzed on three (3) GEM 7000 systems. K+ bias at each test pool was calculated from the low pool to generate hemolysis interferograms. Linear regression was performed to determine the hemolysis level that exceeds the interference limit of 7%.

Results

Hemolysis exceeding the interference limit was ≥ 116 mg/dL for the low K+ and ≥ 147 mg/dL for the high K+ level. These correspond to an elevation of 0.27 mmol/L and 0.37 mmol/L of K+, respectively. Based on this study, the GEM 7000 triggers a hemolysis flag when the detected hemolysis exceeds 115 mg/dL. By default, GEM 7000 hemolysis flags are categorized into mild (116 -300 mg/dL), moderate (301 - 400 mg/dL), and gross (≥401 mg/dL) hemolysis.

Conclusions

The magnitude of the observed increase in K+ (0.277 - 0.295 mmol/L for every 100 mg/dL of hemoglobin) on the GEM 7000 due to in vitro hemolysis is consistent with previously published reports in the literature. Automated hemolysis detection and flagging of K+ results in GEM 7000 overcome the limitation of the inability to detect hemolysis in blood gas samples.
A-367 Development of a Multimodal Point-of-Care Diagnostic Platform to Perform Rapid, Accurate, and Cost-Effective Molecular, Immunochemistry, Clinical Chemistry, and Cytometry Tests
Authors: Charrault E , Chew K , Habibi A , Ramezan T , Currier K , So C , Banaszczyk A , Bai S , Niu V , Lai K , Chang W , Caron D , Pham K , Ghosh O , Khan R , Milbes B , Swadia H , Chien J , Sathyamoorthy K , Naranatt P , Maktabi S , Singh A , Patel T , Izadi Kharazi F , Heltsley R
Published: October 2024

Background

Access to point-of-care (POC) testing can make a significant impact on the quality of care. However, because POC diagnostic platforms available today are expensive and only perform one type of test, clinicians are unable to implement all the POC tests they wish to perform. Fluxergy is developing a multimodal POC diagnostic platform that consolidates diverse diagnostic modalities into a single, compact platform to minimize the cost of POC testing and standardize testing workflow for the most common clinical chemistry, hematology, immunochemistry and molecular tests. This study describes feasibility studies performed to benchmark these assay modalities on the Fluxergy Analyzer.

Methods

Fluxergy Analyzer: The Fluxergy Analyzer integrates conventional detection systems—colorimetric, fluorometric, and electrochemical—into a singular POC platform. This unique design expands -omics testing capabilities, including molecular, immunochemistry, clinical chemistry, and hematology within a single instrument. Benchmarking Feasibility Studies: Molecular benchmarking was performed using a multiplex respiratory panel on contrived samples in UTM/VTM. Immunochemistry benchmarking was performed using a procalcitonin assay on spiked sodium citrate plasma samples. Cytometry benchmarking was performed using a white blood cell count (WBC) assay and testing contrived samples whole blood samples.

Results

For molecular testing, the Fluxergy Analyzer was able to accurately detect flu A, flu B, SARS-CoV-2, and RSV with agreements with the Luminex ARIES® Flu A/B & RSV Assay and Cepheid Xpert® SARS-CoV-2 test results. For immunochemistry testing, the Fluxergy Analyzer accurate quantified PCT levels at 0.3, 0.6, 1.25 and 2.5 ng/mL. For hematology testing, the Fluxergy Analyzer demonstrated a strong correlation across the reportable range against the standard of care HemoCue analyzer. For clinical chemistry testing, the Fluxergy Analyzer demonstrated a strong correlation against the Siemen’s epoc® Blood Analysis System.

Conclusions

The Fluxergy Analyzer is uniquely suited to offer a comprehensive menu of the most common POC tests on a single, cost-effective platform.
B-005 Improved Sensitivity on the Beckman Coulter DxI 9000 Immunoassay Analyzer* Enables Reduction of Required Sample and Reagent Volumes for Immunoassays
Authors: Kuklok S , Lareau R , Thomforde J , Her T , Young A , Thompson T , Tornquist M , Bagley A , Kubista H , Johnson J , Bolstad B , Walt K , Lovett D , Holland M , Mah J , Nelson W , Lengfeld J , Quin M , Bilyeu B , Knutson C , Posnansky M , Malikowski-Hoffarth N , Soller K , Szabo M , Carlson C
Published: October 2024

Background

The Beckman Coulter DxI 9000 Immunoassay Analyzer* includes new technology that improves assay sensitivity capabilities. Such technological advancements include the Lumi-Phos PRO chemiluminescent substrate, a new luminometer, and improved low-volume pipetting capabilities. These enhancements afford opportunities to develop immunoassays using reduced sample and reagent volumes, conserving precious patient samples, minimizing the carbon footprint of plastic packaging, and increasing the number of tests per reagent pack. Studies are presented herein for the Access TSH (3rd IS), Access βhCG (5th IS), and Access Hybritech Total PSA assays to evaluate analytical performance when using decreased sample/reagent volumes on the DxI 9000 analyzer. *The official name is DxI 9000 Access Immunoassay Analyzer.

Methods

To assess performance when using proportionally reduced sample/reagent volumes on the DxI 9000 analyzer compared to standard sample/reagent volumes on the Access 2 Immunoassay System, within-laboratory precision was evaluated following CLSI EP05-A3, limit of quantitation (LoQ) was estimated following CLSI EP17-A2, and accuracy was assessed following CLSI EP09c, 3rd ed.

Results

Results of sensitivity studies are summarized in the table below for assays using reduced sample/reagent volumes on the DxI 9000 analyzer compared to standard volumes on the Access 2 system. Maximum observed LoQ improved 1.4- to 3-fold on the DxI 9000 analyzer, despite employing ∼50% reduction of sample/reagents. Precision and accuracy studies also showed acceptable performance.

Conclusions

The data herein provide evidence for maintained analytical performance goals when using reduced sample and reagent volumes for assays on the DxI 9000 analyzer. The additional sensitivity capability of the DxI 9000 analyzer can be used to reduce the volume of sample and reagents, conserving patient samples and reducing packaging per test. The pipetting accuracy and detection capabilities of the DxI 9000 analyzer provide opportunities for immunoassay developers to drive both improved low-end performance and conservation of resources.
B-006 Use of Sysmex UN-3000 Research Parameters for Semiquantitative Analysis of Urine Microscopic Elements
Authors: Nakashima M , Shelestak H , Lauren M , Chappell M
Published: October 2024

Background

Microscopic examination of urine is an important component of urine analysis. However, it is labor-intensive and requires a skilled microscopist. The Sysmex UN-3000 (Kobe, JP) combines a Siemens CLINITEK Novus (Munich, GER) with a Sysmex UF-5000 flow cytometer and Sysmex UD-10 digital imaging device for fully automated urine analysis. It is FDA-approved for quantitation of red and white blood cells, epithelial cells, casts, and bacteria. It also flags for other particles such as sperm, yeast, pathologic casts, and crystals, which can then be confirmed on the UD-10. We sought to determine if and how the UF-5000 research parameter results could be used for semi-quantitative grading of pathologic casts, squamous epithelial cells, non-squamous epithelial cells, and crystals to match our reporting system.

Methods

Urine samples were analyzed by the UN-3000 and by manual review of urine sediment per laboratory protocols. Epithelial cells and crystals grades were none seen, few, moderate, many. Cast grades were 0, 1-3, 4-10, and >10. Results of manual microscopy were used to determine numerical cutoffs for the UF-5000 results which would agree within one grade in ≥90% of samples. Sperm and yeast are reported as either present or absent. For these particles, manual microscopy was compared to the results of the UF-5000 flagging and subsequent review of the UD-10 images.

Results

Rate of agreement between the methods is shown in the table. For sperm the UN-3000 showed 91.7% sensitivity and 100% specificity; for yeast, 93.8% sensitivity and 97.7% specificity.

Conclusions

We were able to use the research parameters from the UF-5000, in conjunction with the UD-10, to perform semi-quantitative grading. Adoption of this analyzer increases automation, with 70% of samples auto-validating per our protocols, while still conforming to our previous reporting system.
B-010 Intercomparison Study of Methods between Atellica Solution® and CI® Analyzers for Sodium, Potassium, and Chloride
Authors: Garcia-Valdecasas S , Lapeña-Garcia S , Ruiz-Alvarez M , Costales-Lucia T , Moreno-Romero A , Molina-Blas S , Barrionuevo-Gonzalez M
Published: October 2024

Background

Method verification is an essential analysis routinely conducted in accredited Clinical Laboratories whenever a change of method or instrument for a specific analyte is desired.

Objectives

The aim of the study is to verify that the results measured by the Atellica Solution® analyzer (Siemens) and the new CI® analyzer (Siemens) for Sodium, Potassium, and Chloride are interchangeable.

Methods

To conduct the intercomparison study of Sodium, Potassium, and Chloride, the techniques were properly calibrated and controlled on both analyzers. For each assay, 40 patient samples were selected, covering the entire measurement range, and analyzed by both instruments. To determine the degree of agreement between the instruments, a Bland Altman analysis of mean differences and a Passing Bablok regression were performed. Statistics are expressed with their 95% confidence intervals (CI). The evaluation of results was carried out using the statistical program Method Validator.

Results

In both the Bland-Altman and Passing Bablok regression analyses, a slight constant systematic error was detected for all three assays, as the 95% confidence interval of the observed mean difference and the 95% confidence interval of the intercept of the regression line do not include zero. No systematic proportional differences were observed based on the slope, as the 95% confidence interval includes the value one

Conclusions

The small constant systematic differences found in the analyses should be re-evaluated after performing a new calibration of the methods. In none of the cases are the differences clinically significant, as they do not exceed the total error established in our quality specification. Therefore, it can be concluded that the Atellica Solution® and CI 1900® analyzers are interchangeable for Sodium, Potassium, and Chloride assays
B-022 A New DNA Size-Selection Technology:Methods for Isolating, Capturing, and Recovery of Target Macromolecules by Gel Electrophoresis
Authors: Nix P T
Published: October 2024

Background

The ability to recover DNA fragments in high quantity and purity from agarose gel is an important need for researchers in molecular biology laboratories for downstream applications such as testing and sequencing. There are multiple established methods and corresponding commercial products available at researchers’ disposal. Despite the availability of many methods, researchers often face a trade-off decision between fast and simple methods with low yield and poor DNA quality, and time-consuming and expensive methods with higher yields and better purity.

Methods

Gene Stix (ElectroSep) is a new system for recovery of DNA/RNA from an electrophoresis gel. Using the power of electrophoresis to separate nucleic acids based on size (a well-known technique), the Gene Stix, for the first time, allows one to recover nucleic acids directly from the gel. Gene Stix consisted of a cationic membrane which is inserted (in front of the nucleic acid of interest) into the electrophoresis gel after the nucleic acids are resolved from other contaminants in a separate step. After the Gene Stix is inserted in front of the DNA, the gel is re-run for a short period of time, binding the DNA to the Gene Stix. The Gene Stix is removed from the gel (carrying the DNA) and the DNA is recovered by elution using a special buffer.

Results

Electro-Sep technology allows DNA recovery around 85% and may lead up to 35% process efficiency for purification. It maximizes the process efficiency by not requiring damaging UV sensitive dyes in samples or cutting gel bands and allowing multiple Gene Stix used with one sample. Unique serial numbering system provides unambiguous sample identification.

Conclusions

The yield from different methods varies, however, it is typically at around 60-70%. Many of the commercially available DNA purification kits require around 25-30 minutes for purification. Moreover, the process with available methods could be laborious requiring cutting the gel bands, using UV dyes in sample, or simply requiring specialized gel electrophoresis equipment. Electro-Sep technology (and Gene Stix product using the technology), designed to recover size-selected DNA from agarose gel, provides a viable option that is rapid, easy-to-use yet resulting in high DNA recovery.
B-029 Evaluation of the Analytical Performance of Creatine Kinase, Lactate dehydrogenase L-P, Myoglobin Assays on the Atellica CI Analyzer
Authors: Carter R H , Belth B , Ozgen N , Shalhoub V , Camacho J , Snyder J , Leipold H
Published: October 2024

Background

The Atellica® CI Analyzer is an automated, mid-throughput, integrated chemistry and immunoassay analyzer utilizing both Atellica® CH and Atellica® IM assays. This study was designed to evaluate the analytical performance of the Atellica® CH Creatine Kinase (CK_L), Lactate dehydrogenase L-P (LDLP), and Atellica IM Myoglobin (MYO) Assays on the Atellica CI Analyzer.

Methods

The Atellica CI assays use the same reagents and calibrators as the Atellica CH and IM assays. Precision studies were performed according to CLSI EP05-A3 using human serum samples. One aliquot of each sample pool was tested in duplicate in two runs per day >2 hours apart on each analyzer for 20 days. MC studies were performed according to CLSI EP09-A3. Individual human serum samples were analyzed using the Atellica CH, Atellica IM, and Atellica CI Analyzers. LoB, LoD, LoQ were determined according to CLSI EP17-A2.

Results

Representative precision and MC results across indicated sample ranges are listed for each assay in the table. Over the three assays tested, %CVs for repeatability were <2.6% and %CVs for within-lab were <4.5%. Slopes determined using the Deming linear regression model were approximately equal to 1. LoB, LoD, LoQ were 5, 8, and 15 U/L for CK_L; 2, 4, and 11 U/L for LDLP; and 3,00, 6.00, and 6.00 ng/mL (µg/L) for MYO assays, respectively.

Conclusions

Atellica CH CK_L and LDLP, and Atellica IM MYO Assays on the Atellica CI Analyzer demonstrated good precision and equivalent performance to the same assays on Atellica IM and CH Analyzers.