i-STAT Portable Clinical Analyzer Research Articles

HEALTH STATUS OF NAZCA BOOBIES (SULA GRANTI) ON DAPHNE MAJOR ISLAND IN THE GALÁPAGOS DETERMINED BY HEMATOLOGY, BIOCHEMISTRY, AND PHYSICAL EXAMINATION.

Island species are particularly vulnerable to environmental disturbances and introduced pathogens. Conducting health assessments of wild populations in the Galápagos improves the ability of wildlife managers and veterinarians to detect deteriorations in health status. Seabirds in particular are useful species to monitor due to their colonial breeding and wide migration range. Nazca boobies (Sula granti) in a breeding colony at Daphne Major (n = 30) were given physical examinations, and blood samples were collected for hematology and biochemistry using an iSTAT Portable Clinical Analyzer. Female boobies had longer wing length than males, as well as lower blood urea nitrogen, creatinine, and white blood cell counts. This could be attributed to sexual dimorphism or differences in foraging and mating strategies between the sexes. The time between capture and blood collection had a significant inverse relationship on plasma sodium, potassium, hemoglobin, anion gaps, and lymphocyte counts, suggesting that blood sampling in Nazca boobies should be done in less than 5 m to avoid the impacts of stress on hematological parameters. This is the first health assessment on the breeding colony of Nazca boobies at Daphne Major, and the results can inform future monitoring in this species as well as other sulids.

Associations between piglet umbilical blood hematological criteria, birth order, birth interval, colostrum intake, and piglet survival.

A total of 656 pigs (623 live-born and 33 stillborn) from 43 sows were used to evaluate hematological criteria at birth and their association with piglet survival. At birth of each piglet, birth time and order within the litter, weight, umbilical cord status (intact or ruptured) and whether the pig was live-born or stillborn were recorded. A 200µL sample of blood from the umbilical cord was collected and immediately analyzed for concentrations of glucose, oxygen partial pressure (pO2), carbon dioxide partial pressure (pCO2), pH, base excess (BE), bicarbonate (HCO3), saturated oxygen (sO2), total carbon dioxide (TCO2), sodium, potassium, ionized calcium (iCa), hematocrit (Hct), and hemoglobin (Hb) on a hand held iStat portable clinical analyzer (iStat Alinity, Abbott Point of Care Inc., Princeton, NJ). Piglets were categorized into quartiles based on birth order and cumulative birth interval (CumBI). Live-born pigs had higher (P < 0.01) umbilical cord blood pH, HCO3, BE, sO2, TCO2, and birth weight compared with stillborn pigs, but lower (P < 0.01) pCO2, K, iCa, and glucose compared with stillborn pigs. Pigs with intact umbilical cords at birth were associated with higher (P < 0.01) blood pH, HCO3, BE, and TCO2 compared with piglets born with a ruptured umbilical cord. Pigs with intact umbilical cords were associated with lower (P < 0.01) Hct and Hb concentrations and born earlier (P < 0.01) in the birth order compared with pigs born with a ruptured umbilical cord. Pigs that did not survive to weaning had lower (P < 0.01) umbilical cord blood pH, HCO3, BE, sO2, TCO2, Na, glucose, and birth weight, and 24 hr weight compared with pigs alive at weaning. Pigs born in the first quartile for CumBI had higher (P <0.05) pH compared with pigs in the other three quartiles. Umbilical cord blood HCO3, BE, and TCO2 decreased (P <0.05) with each change in CumBI quartile from first to last. Blood glucose was lowest (P <0.05) in pigs born before 44 min and highest in pigs born after 164 min. Umbilical cord blood pH, HCO3, BE, TCO2, Na, glucose, Hct, and Hb were positively associated (P <0.001) with colostrum intake, indicating increased blood values resulted in higher colostrum intake. Although a pig may be live-born, their survival to 24 hr and to weaning is reduced when blood pH, HCO3, BE, and sO2 are lower reiterating the importance of management practices that can reduce the birth interval between pigs and the number of pigs experiencing moderate to severe hypoxia.

Quantum Blue Reduces the Severity of Woody Breast Myopathy via Modulation of Oxygen Homeostasis-Related Genes in Broiler Chickens.

The incidence of woody breast (WB) is increasing on a global scale representing a significant welfare problem and economic burden to the poultry industry and for which there is no effective treatment due to its unknown etiology. In this study, using diffuse reflectance spectroscopy (DRS) coupled with iSTAT portable clinical analyzer, we provide evidence that the circulatory- and breast muscle-oxygen homeostasis is dysregulated [low oxygen and hemoglobin (HB) levels] in chickens with WB myopathy compared to healthy counterparts. Molecular analysis showed that blood HB subunit Mu (HBM), Zeta (HBZ), and hephaestin (HEPH) expression were significantly down regulated; however, the expression of the subunit rho of HB beta (HBBR) was upregulated in chicken with WB compared to healthy counterparts. The breast muscle HBBR, HBE, HBZ, and hypoxia-inducible factor prolyl hydroxylase 2 (PHD2) mRNA abundances were significantly down regulated in WB-affected compared to normal birds. The expression of HIF-1α at mRNA and protein levels was significantly induced in breasts of WB-affected compared to unaffected birds confirming a local hypoxic status. The phosphorylated levels of the upstream mediators AKT at Ser473 site, mTOR at Ser2481 site, and PI3K P85 at Tyr458 site, as well as their mRNA levels were significantly increased in breasts of WB-affected birds. In attempt to identify a nutritional strategy to reduce WB incidence, male broiler chicks (Cobb 500, n = 576) were randomly distributed into 48 floor pens and subjected to six treatments (12 birds/pen; 8 pens/treatment): a nutrient adequate control group (PC), the PC supplemented with 0.3% myo-inositol (PC + MI), a negative control (NC) deficient in available P and Ca by 0.15 and 0.16%, respectively, the NC fed with quantum blue (QB) at 500 (NC + 500 FTU), 1,000 (NC + 1,000 FTU), or 2,000 FTU/kg of feed (NC + 2,000 FTU). Although QB-enriched diets did not affect growth performances (FCR and FE), it did reduce the severity of WB by 5% compared to the PC diet. This effect is mediated by reversing the expression profile of oxygen homeostasis-related genes; i.e., significant down regulation of HBBR and upregulation of HBM, HBZ, and HEPH in blood, as well as a significant upregulation of HBA1, HBBR, HBE, HBZ, and PHD2 in breast muscle compared to the positive control.

Health status assessment of traumatic injury freshwater turtles.

A group of injured yellow-bellied sliders (Trachemys scripta) and river cooters (Pseudemys concinna) were evaluated for a variety of health values at presentation to the NC State Turtle Rescue Team and prior to release. An i-STAT Portable Clinical Analyzer and CG8+ cartridges were used to determine venous blood gas and biochemical values, the packed cell volume (PCV) and total protein were evaluated using hematocrit tubes and high speed centrifugation, and a differential WBC percentage was determined manually with Diff-Quick stained blood smear slides. Forty-six turtles were sampled on presentation and twenty-three of those were sampled again prior to release. Blood values were analyzed for significant differences between samples collected at presentation and prior to release, as well as differences between surviving and non-surviving turtles. Five variables were identified as significantly different between presenting and recuperated samples: pH, pCO2, Glu, % heterophils, and % eosinophils. When comparing samples between turtles that survived versus those that did not, two variables were identified as being significant prognostic indicators; lactate and PCV. Identification of these significant variables can aid in determining patient prognosis and triage therapy for injured aquatic turtles.

EVALUATION OF THE I-STAT PORTABLE CLINICAL ANALYZER FOR MEASUREMENT OF IONIZED CALCIUM AND SELECTED BLOOD CHEMISTRY VALUES IN ASIAN ELEPHANTS (ELEPHAS MAXIMUS).

Thei-STAT® portable clinical analyzer (PCA) provides patient-side results for hematologic, biochemical, and blood gas values when immediate results are desired. This analyzer is commonly used in nondomestic animals; however, validation of this method in comparison with traditional benchtop methods should be performed for each species. In this study, the i-STAT PCA was compared with the Radiometer ABL 800 Flex benchtop analyzer using 24 heparinized whole blood samples obtained from healthy E. maximus . In addition, the effect of sample storage was evaluated on the i-STAT PCA. Analytes evaluated were hydrogen ion concentration (pH), glucose, potassium (K+), sodium (Na+), bicarbonate (HCO3-), total carbon dioxide (TCO2), partial pressure of carbon dioxide (PCO2), and ionized calcium (iCa2+). Statistical analysis using correlation coefficients, Passing-Bablok regression analysis, and Bland-Altman plots found good agreement between results from samples run immediately after phlebotomy and 4 hr postsampling on the i-STAT PCA with the exception of K+, which is known to change with sample storage. Comparison of the results from the two analyzers at 4 hr postsampling found very strong or strong correlation in all values except K+, with statistically significant bias in all values except glucose and PCO2. Despite bias, mean differences assessed via Bland-Altman plots were clinically acceptable for all analytes excluding K+. Within the reference range for iCa2+, the iCa2+ values obtained by the i-STAT PCA and Radiometer ABL 800 Flex were close in value, however in light of the constant and proportionate biases detected, overestimation at higher values and underestimation at lower values of iCa2+ by the i-STAT PCA would be of potential concern. This study supports the use of the i-STAT PCA for the evaluation of these analytes, with the exception of K+, in the Asian elephant.

Influence of Temperature, Salinity, and Dissolved Oxygen on the Stress Response of Bull (Carcharhinus leucas) and Bonnethead (Sphyrna tiburo) Sharks after Capture and Handling

ABSTRACT Hyatt, M.W.; Anderson, P.A., and O'Donnell, P.M., 2018. Influence of temperature, salinity, and dissolved oxygen on the stress response of bull (Carcharhinus leucas) and bonnethead (Sphyrna tiburo) sharks after capture and handling. Capture and handling stress can induce acidosis in sharks. This response, endured during commercial bycatch and in catch-and-release recreational fisheries, could be exacerbated in certain environmental conditions. To assess environmental influence on stress response, changes in acid-base, blood gas, and metabolite analytes (pH, pCO2, and lactate) measured with the i-STAT portable clinical analyzer were evaluated immediately after capture and removal from gillnets among wild bull (Carcharhinus leucas) and bonnethead (Sphyrna tiburo) sharks caught in waters of differing temperature (T), salinity (Sal), and dissolved oxygen (DO). Time from capture to blood collection (C-BD) was also recorded. Effects of T, Sal, DO, and C-BD on acid-base physiology were evaluated by mode...

Comparison ofpH, Lactate, and Glucose Analysis of Equine Synovial Fluid using a Portable Clinical Analyzer with a Bench‐Top Blood Gas Analyzer

To compare agreement between a portable clinical analyzer and laboratory-based bench-top analyzer for analysis of pH, lactate, and glucose concentrations in synovial fluid. Prospective experimental study. Clinically normal horses (n=8); 6 horses euthanatized for reasons unrelated to the study; 11 horses that had synoviocentesis for reasons other than sepsis; 7 horses that had synoviocentesis for evaluation of sepsis; and 2 horses without recorded clinical data. Median age of horses was 8 years (range, 1 day to 24 years). Supernatant from each synovial fluid sample was analyzed for pH, lactate, and glucose concentrations using an ABL 705 laboratory-based bench-top analyzer and i-STAT portable clinical analyzer. Bland-Altman plots were constructed and concordance analysis performed to determine bias and agreement between the 2 analyzers. There was acceptable agreement between analyzers for lactate and glucose concentrations, with biases of 0.198 mmol/L and 9 mg/dL and concordance correlation coefficients of 0.97 and 0.96 for lactate and glucose, respectively. The agreement between analyzers for pH was not acceptable, with a bias of -0.057 and concordance correlation coefficient of 0.89. This study found that the portable clinical analyzer performed similarly to the bench-top blood gas analyzer for evaluation of lactate and glucose concentrations, but not pH, in synovial fluid.

Polwarth and Texel ewe parturition duration and its association with lamb birth asphyxia12

The objective of the present study was to test the hypothesis that parturition duration is related to birth asphyxia in lambs and that asphyxia affects newborn lamb viability and vigor. Two sire and dam genotypes (Texel: TX; Polwarth: PW) and their crosses were represented in the study. Eighty lambs (25 PW sire × PW dam, 13 TX × TX, 25 TX × PW, and 17 PW × TX) born to 69 grazing ewes were used. At birth, the log₁₀ length of the second stage of parturition, birth weight, placental weight, and several body measurements were recorded on all lambs, and jugular blood samples were analyzed with the i-Stat Portable Clinical Analyzer (Abbott, Montevideo, Uruguay). A modified Apgar viability score at birth and lamb behavior during their first hour of life were recorded. Brain weight, muscle:bone ratio, and bone density were recorded in 20 male lambs (5 from each breed group) that were euthanized and dissected 24 h after birth. Data were analyzed by linear regression, least squares ANOVA, and ordinal and binary logistic regressions. Mean blood gas and acid-base variables were 7.21 ± 0.09 for pH, 18.4 ± 9.8 mmHg for partial pressure of oxygen, 53 ± 12.5 mmHg for partial pressure of carbon dioxide, and -4 ± 5.1 mmol/L for extracellular fluid base excess. Parturition duration increased with birth weight (P < 0.001) and was shorter in TX ewes (P < 0.001), female lambs (P < 0.05), twins (P < 0.09), and twin females (sex × litter size interaction, P < 0.02). Twenty-six (32.9%) lambs were born asphyxiated (pO₂ < 10 mmHg or pH <7.1). Parturition duration increased the risk of asphyxia (P < 0.001), decreased the viability score (P < 0.001), and increased the latency to suckle the udder (P < 0.05). Twin-born lambs presented at birth a 16-fold greater risk of asphyxia (P < 0.01) and reduced placental efficiency (P < 0.05). Texel-sired lambs appeared immature at birth, with less bone density (P < 0.05), smaller brain (P < 0.05), shorter forelimbs (P < 0.05), greater anterior (P < 0.001) and posterior (P < 0.05) neck circumference, and greater muscle:bone ratio (P < 0.05). Immaturity may explain greater TX biotype survival. Together these results demonstrate that a relationship exists between parturition duration, neonatal viability and behavior, and acid-base balance values in single- and twin-born lambs, suggesting that birth asphyxia is an important risk factor in perinatal lamb mortality.

Blood Gas, Oxygen Saturation, pH, and Lactate Values in Elasmobranch Blood Measured with a Commercially Available Portable Clinical Analyzer and Standard Laboratory Instruments

Blood gas, pH, and lactate data are often used to assess the physiological status and health of fish and can often be most valuable when blood samples are analyzed immediately after collection. Portable clinical analyzers allow these measurements to be made easily in the field. However, these instruments are designed for clinical use and thus process samples at 37 degrees C. A few studies have validated the use of portable clinical analyzers for assessing blood gases and acid-base profiles in teleosts, but equivalent data are not available for elasmobranchs. We therefore examined the relationship of blood gas, pH, and lactate values measured with an i-STAT portable clinical analyzer with those measured using standard laboratory blood gas (thermostatted to 25 degrees C) and lactate analyzers in samples taken from three species of carcharhiniform sharks. We found tight correlations (r2 > 0.90) between these methods for pH, pO2, pCO2, and lactate level values. We thus developed species-specific equations for converting blood values measured with an i-STAT portable clinical analyzer to those taken at 25 degrees C. Additional studies need to address a wider range of temperatures and elasmobranch species.

Efficacy of anthelminthic control programs against naturalMuellerius capillarisinfection in sheep in the north-west of Spain. Effect on blood gases and pH in venous blood samples

The field efficacy of a single dose treatment against natural M. capillaris infection using different anthelmintic drugs, extensively employed in ovine parasite control programs in Galicia (N.W. Spain), and the effect of protostrongylid infection on ovine respiratory functions, were evaluated. Five groups (n = 5) of ewes were used in this study; animals were treated with injectable ivermectin 10.2 mg/kg), levamisole (7.5 mg/kg) and albendazole (5 mg/kg) and monitored at 0, 7, 21, 42 and 63 days posttreatment (d.p.t.) by enumeration of the lungworm larvae per gram of faeces (l.p.g.) and determination of gas tension and pH in venous blood using an i-Stat portable clinical analyzer. No statistical difference was found either in larval elimination between untreated and treated groups or in the reduction in larval counts in all of the treated groups. A significant increase in partial oxygen tension (pO2) and saturation (sO2) between day 0 and 7 p.t. was observed in all treated animals. These values decreased significantly at day 21 to previous levels. There were no statistical differences in blood gases between uninfected and treated groups. We can conclude that under Galician field conditions, parasitic control programs are not totally effective against M. capillaris infection.

CXCR4 Expression and Biological Activity Is Dependent on Oxygen Partial Pressure in Acute Myeloid Leukemia.

CXCR4, the receptor for bone marrow stroma derived SDF-1, has recently been studied in normal hematopoiesis and hematologic malignancies. Increased expression of CXCR4 by leukemic blasts has been reported by us and others (Konoplev S. et al, Cancer 2007) to be associated with poor prognosis in acute myeloid leukemia (AML). However, all in-vitro studies are usually carried out under unphysiological, i.e. normoxic (21% O2) conditions. We hypothesized that the pO2 in vitro has major impact on the expression of CXCR4, a key receptor for cell migration and intracellular signalling. Thus, pO2 of bone marrow aspirates was measured using the i-STAT Portable Clinical Analyzer and a hypoxic workstation was used providing constant low oxygen content. Surface and total CXCR4 expression was examined in leukemic cell lines and patient samples by flow cytometry, confocal microscopy and Western blotting (WB). In 19 patients, the median pO2 of the bone marrow was determined as 46.1±12.8 mmHg (6.1±1.7%) with no significant difference between patients with AML (n=7, pO2 41.3±11.2 mmHg) and patients in CR (n=12, pO2 48.3±15.9 mmHg). This level of hypoxia significantly increases surface and total expression of CXCR4 in the leukemic cell lines U937 and OCI-AML3 as well as in samples from patients with AML, as compared to normoxic conditions (~2.8fold increase). This increase happened mainly within the first 2–8 hours of hypoxia and was unrelated to increased CXCR4 transcription, as shown by PCR. Re-oxygenation of leukemic cells resulted in a statistical significant degradation of CXCR4 (~3fold decrease) in all examined cell lines and patient samples (n=10). This loss of CXCR4 is very rapid (within 5 minutes of re-oxygenation) and was detected by flow cytometry, confocal microscopy and WB. This phenomenon was independent of proteasome activity and ATP. Detailed analysis of membraneous lipid rafts by sucrose density separation, cholesterol depletion and flow cytometry analysis for GM1 gangliosides showed structural (distinct re-distribution of Lck in lipid rafts) and quantitative changes (loss of cholesterol and CXCR4) during re-oxygenation. Moreover, part of the loss of CXCR4 can be attributed to sequestration of microparticles into the extracellular environment as shown by WB of supernatant of re-oxygenated cells and by a significant increase (~1.5fold) in the amount of microparticles released by cells (cell lines U937 and OCI-AML3 and additional patient samples) during the process of re-oxygenation, as measured by flow cytometry. In summary, this study determined the oxygen content of CR and leukemic bone marrow samples as 6.1±1.7%. This pO2 is associated with an increase in CXCR4 expression on AML cells, while re-oxygenation leads to a rapid decrease of CXCR4, perhaps in part by shedding of CXCR4- containing microparticles. These studies point to the importance of studying leukemic blasts under physiologic, i.e. hypoxic conditions.

Evaluation of the i-STAT Portable Clinical Analyzer in Chickens (Gallus Gallus)

The i-STAT portable clinical analyzer (PCA) was evaluated for performance in avian species. With the EG7+ cartridge, which provided results for hydrogen ion concentration, oxygen tension, carbon dioxide tension, sodium, potassium, ionized calcium, hematocrit, and various calculated parameters, analytical accuracy and precision were tested by comparing obtained values to those of established traditional blood gas and chemistry analyzers. Deming's regression and bias plots were used to compare i-STAT results with those obtained by laboratory professionals using benchtop analyzers. The reliability of the i-STAT PCA with EG7+ cartridges was good, with 0-5.7% system failures in measured values. Regression statistics were good for all blood gas analytes and acceptable for electrolytes and calculated parameters, except for potassium and base excess, for which the regression data or the discrepancy between the methods was too large. The system was reliable and easy to use and had an overall acceptable accuracy in avian species. These features, together with portability and small required blood volumes, make the i-STAT suitable for point-of-care use in critical avian patients, although single values require careful interpretation.

The reliability of the i-STAT clinical portable analyser

The purpose of this investigation was to assess the reliability of the i-STAT clinical portable analyser and CG(4)(+) cartridge measures of blood pH, partial pressures of O(2) (pO(2)) and CO(2) (pCO(2)), bicarbonate ([HCO(3)(-)]), base excess (BE), total carbon dioxide (TCO(2)), oxygen saturation (sO(2)) and blood lactate ([BLa(-)]) at various exercise intensities. A comparison between [BLa(-)] measured by the i-STAT and the Accusport lactate analysers during an intermittent treadmill run was also undertaken. The technical error of measurement (TEM%) at rest, at moderate (200W) and maximal exercise (V O(2)max) was acceptable (<15%) for all parameters. The intra-class correlation coefficients for each analyte ranged from weak-to-strong across resting (ICC=0.19-0.96) and moderate (ICC=0.30-0.96) exercise intensities. The ICC for all analytes were observed to be strong following maximal intensity exercise (ICC=0.77-0.95). The comparison of the [BLa(-)] measures between the i-STAT and Accusport showed that the difference between measures was acceptable at both low (<4mmolL(-1)) (-0.39+/-0.27mmolL(-1)), moderate to high concentrations (>4mmolL(-1)) (0.58+/-1.22mmolL(-1)), and across all [BLa(-)] data (0.36+/-1.13mmolL(-1)). In conclusion, the i-STAT clinical analyser and CG(4)(+) cartridge provides reliable measures of a number of blood parameters across exercise intensities. The [BLa(-)] measures from the i-STAT analyser are consistent with that of the Accusport lactate analyser.

Use of the i-STAT portable clinical analyzer in mice

The use of portable chemistry analyzers is an attractive option for obtaining clinical pathology panels in mice, because these analyzers require only small volumes of whole blood. However, in studies with other animals, portable analyzers do not always agree with results obtained using standard laboratory equipment. The authors evaluated the use of the i-STAT handheld portable clinical analyzer compared to the use of standard nonportable laboratory instruments in mice. As shown with other species, the i-STAT results did not always agree with standard laboratory instruments; however, the i-STAT does show reliability for certain chemistry assays.

Evaluation of an improved blood-conserving POCT sampling system

To evaluate a modified point-of-care (POCT) testing i-STAT analyzing cartridge that connects directly to the sampling port of a blood-conserving sampling line. In an in vitro setup, blood samples were drawn from a blood-conserving sampling line connected to a miniature cardiopulmonary bypass (CPB) system. Blood collection from the sampling port was either performed with a syringe necessitating subsequent sample loading on a standard i-STAT cartridge (conventional procedure) or with a modified i-STAT sampling cartridge allowing blood flow from the sampling port directly into the cartridge (modified procedure). The loaded cartridges were subsequently inserted into the i-STAT Portable Clinical Analyzer for sample analysis. Multiple parameters such as blood gases, electrolytes, hematocrit, and glucose were measured. A series of 30 paired measurements was performed. Corresponding series of values were compared using linear regression analysis and Bland-Altman bias analysis (P < 0.05). Twenty-five complete measurement series consisting of 12 parameters (pH, pCO(2), pO(2), SO(2), base excess, bicarbonate concentration, sodium, potassium, ionized calcium, hemoglobin concentration, hematocrit, glucose) were evaluated. Linear regression analysis between the two sampling methods tested demonstrated an excellent correlation for all parameters (Pearson correlation coefficients: 0.859-0.999). Bias and precision between corresponding series showed clinically acceptable performance levels for all parameters. The modified i-STAT sampling cartridge allows reliable diagnostic blood sampling directly from a blood-conserving sampling line. The technique presented is also applicable to other POCT systems, thus reducing diagnostic blood loss because of the minimal amount of blood required for analysis.

Stability of i-Stat EC6+ cartridges: effect of storage temperature on shelf life.

Point-of-care testing is a valuable tool in many settings, including remote environments (1). The i-STAT Portable Clinical Blood Analyzer (i-STAT Corp.) has been tested extensively and has been used during spaceflight as both a research (2)(3) and a clinical(4) tool. One disadvantage of the Portable Clinical Blood Analyzer is the requirement for refrigerated storage for consumables (ambient storage is limited to 2 weeks). The effects of re-refrigeration after transient ambient storage are undocumented, but this is discouraged by the manufacturer. We determined the effects of long-term ambient storage and the effects of re-refrigeration on the performance of i-STAT EC6+ cartridges. Cartridges were stored under one of three treatment conditions: controlled temperature (refrigerated; 2–8 °C), room temperature (18–25 °C), or re-refrigerated. The re-refrigerated cartridges started the study at room temperature and were placed in the refrigerator after a specified number of days. For example, cartridges in the re-refrigerated 16-day group were held at room temperature for 16 days and then were placed in the refrigerator. Subsets were analyzed on study day 23, and after 1 month, 2 months, and so forth. We used two levels of aqueous controls (Bionostics Corp.) and two levels of blood controls (Hematronix). Each group consisted of 20 cartridges: 6 Bionostics level 1 controls, 6 Bionostics level 3, 4 Hematronix low controls, and 4 Hematronix high controls. Cartridges and aqueous controls were single lots; blood controls were from three lots (expiration constraints). The limit ranges (levels 1 and 3, respectively) of each lot of each control (from package inserts) were as follows: pH, 7.130–7.230 and 7.647–7.747; ionized calcium (iCa), 1.47–1.69 and 0.71–0.87 mmol/L; glucose, 2.2–3.2 and 13.4–19.8 mmol/L; sodium, 116–124 and 156–166 mmol/L; and potassium, 2.0–2.8 and 5.8–6.8 mmol/L. The overall hematocrit control limit range was 26–30% packed cell volume (PCV) for the …

Home sodium monitoring in patients with diabetes insipidus

Objective: To determine whether home care givers can accurately measure plasma sodium in children with diabetes insipidus (DI) by using an I-STAT portable clinical analyzer (PCA) and to collect preliminary data on home PCA use. Study design: Care givers of 4 children with DI and impaired thirst or inability to access water freely were instructed in PCA use. During an initial preclinical phase, the accuracy of sodium concentration measured by care givers was assessed by comparison to simultaneous analysis in a clinical laboratory. Participants were subsequently randomly assigned to daily home PCA monitoring or routine care. All participants crossed over from their original randomized group assignment to the alternate group. Results: After a single education session, all care givers were able to perform PCA testing. There was good correlation between PCA and laboratory sodium (r = 0.92). On the basis of Error Grid Analysis, use of the PCA sodium would have resulted in treatment decisions identical to those made based on the laboratory sodium value in 62 of 66 instances. Four minor differences in treatment would have occurred. There was no statistically significant difference in clinical outcome during daily monitoring versus routine care. Conclusions: Results obtained by care givers using the PCA are sufficiently reliable for assessment of fluid status and making treatment decisions. (J Pediatr 2002;141:618-24)

Impact of i-STAT Portable Clinical Analyzer on Blood Loss from Patients in the Neonatal Intensive Care Unit

*From the Departments of Pathology and †Pediatrics, Saint Barnabas Medical Center, Livingston, New Jersey.

Evaluation of i-STAT portable clinical analyzer in a neonatal and pediatric intensive care unit

Objective: To evaluate the Point-of-Care (POC) i-STAT system for measuring blood gases (pH, pC0 2, p0 2) and whole blood electrolytes (sodium, Na +; potassium, K + and ionized calcium, iCa 2+) in the neonatal and pediatric intensive care units. Design and Methods: The i-STAT system was evaluated for imprecision, necessity of running quality control and accuracy. Comparison of patients' samples analyzed by the i-STAT system and the Ciba Corning 288 blood gas analyzer were performed. The reliability of the i-STAT system when performed by non-laboratory personnel was assessed. Results: The system was evaluated for imprecision and linearity using three concentrations of aqueous standards. Except for p0 2, the %CVs were <3.0 for all the analytes (pH, pC0 2, Na +; K + and iCa 2+) at all the three concentrations. Using whole blood studies the precision data gave %CVs that were <3.5 for all the analytes. Linearity studies showed good linearity over the five different concentrations tested. Comparison of the i-STAT and the Ciba Corning 288 blood gas analyzer was assessed by split sample measurement. Patients' results from the i-STAT correlated well with the Ciba Corning 288 blood gas analyzer ( r = 0.99 for pH, pC0 2, and p0 2 and 0.95 to 0.99 for Na +; and K +) with the exception of iCa 2+) ( r = 0.73). There was no significant difference in the results when operated by PICU/NICU nurses or laboratory personnel. A further study was made to assess whether routine quality control (QC) samples are necessary when using the i-STAT system. The regression analysis (slope and correlation coefficient) of the results from instruments run with and without QC samples gave results close to 1, indicating that there is no need to run additional quality control (QC). Conclusion: The POC testing analyzer i-STAT is a reliable alternative to the traditional blood gas analyzers and provides marginal improvement in turnaround time when compared with the service received from the PICU/NICU laboratory. Costs need to be carefully controlled.

Evaluation of i-STAT portable clinical analyzer in a hemodialysis unit

Objective: To evaluate a hand held portable i-STAT analyzer used for point-of-care testing in a hemodialysis unit. Design and Methods: Imprecision and comparison studies. Assays by nonlaboratory personnel. Results: Study of both quality control solutions and hemodialysis patients' duplicate blood specimens with 6+, E3+, EC6+, and EC8+ cartridges both gave CVs for sodium, potassium, chloride, pH, and ionized calcium of 0 to 2.2%. CVs for hematocrit, glucose and pCO 2 for whole blood duplicates were 4.6, 3.5, and 4.0%. The mean differences between i-STAT and central laboratory values for the above compounds and urea, when expressed as a % of mean central laboratory values were 0.2 and 3.1 % except for an ionized calcium value of 4.3% (for which there is an explanation) and for glucose (11 %) that were both higher for i-STAT. Preliminary data suggest that sodium, potassium, ionized calcium, and pH can be assayed in the aqueous dialysate fluid used for hemodialysis. Conclusions: We confirm previous reports that i-STAT cartridges give simple, rapid, and reliable values for sodium, potassium, chloride, urea, glucose, and hematocrit that are clinically acceptable when performed by nonlaboratorians, but also suggest the same conclusions apply to ionized calcium, pH, and p co 2 The hemodialysis unit may prove to be one of several hospital units where the analyzer has considerable value.