Skip to main content

John Griffith Toffaletti

Professor in Pathology
Pathology
Duke Box 3015, Durham, NC 27710
DUHS Central Automated Lab Rm, Durham, NC 27705

Selected Publications


Comparison of Creatinine, Urea, Ionized Calcium, and Bicarbonate Methods by 2 POC Systems and a Mainframe Chemistry Analyzer.

Journal Article J Appl Lab Med · March 6, 2023 BACKGROUND: The i-STAT (iST) and GEM Premier ChemSTAT (ChmST) are point-of-care systems that measure electrolytes, metabolites, acid-base parameters, and hematocrit on blood. We compared results for creatinine, urea (blood urea nitrogen [BUN]), total carbo ... Full text Link to item Cite

Evaluating the Association Between Fibrinogen and Rotational Thromboelastometry and the Progression to Severe Obstetric Hemorrhage.

Journal Article Clin Appl Thromb Hemost · 2023 AIM: This study aims to investigate the ability of fibrinogen and rotational thromboelastometry (ROTEM) parameters measured at obstetric hemorrhage protocol initiation to predict severe hemorrhage. METHODS: In this retrospective study we included patients ... Full text Link to item Cite

Retrospective Analysis of Quality Control Data Using Pooled Blood to Compare Agreement within Two Models of Blood Gas Analyzers.

Journal Article J Appl Lab Med · September 1, 2021 BACKGROUND: Two previous reports from the same group concluded that the analytical reliability of Instrumentation Laboratory GEM4000 analyzers (GEM4K) deteriorated during a 24-hour period, based on results between samples from the same patient but collecte ... Full text Link to item Cite

Blood Gases and Critical Care Testing: Physiology, Clinical Interpretations, and Laboratory Applications

Book · January 1, 2021 Blood gas tests are a group of tests that are widely used and essential for the evaluation and management of a patient’s ventilation, oxygenation, and acid-base balance, often in emergent situations, and along with blood gases are other critical care analy ... Full text Cite

Using α-Angle and A10 ROTEM Parameters for Earlier Information on Clotting Status in Surgery, Postpartum Hemorrhage, and ICU Patients

Journal Article Point of Care · June 1, 2019 Background We determined if the earlier ROTEM (rotational thromboelastometry) parameters (α-angle and amplitude at 10 minutes [A10]) could replace the later-reported maximum amplitude (maximum clot firmness [MCF]) in cardiothoracic surgery (C/T OR), postpa ... Full text Cite

Use of Earlier-Reported Rotational Thromboelastometry Parameters to Evaluate Clotting Status, Fibrinogen, and Platelet Activities in Postpartum Hemorrhage Compared to Surgery and Intensive Care Patients.

Journal Article Anesth Analg · March 2019 BACKGROUND: Rotational thromboelastometry (ROTEM) can provide clinical information in 10-20 minutes for guiding administration of fibrinogen, platelets, and fresh frozen plasma products. While ROTEM testing is well established for cardiac and other surgeri ... Full text Link to item Cite

Effect of beef ingestion by humans on plasma concentrations of creatinine, urea, and cystatin C.

Journal Article Clin Biochem · August 2018 PURPOSE: The effect of eating meat on serum concentrations of creatinine has varied among previous reports, with some finding no effect and others finding 50-100% increases, which appears related to how the beef is cooked. For other analytes related to kid ... Full text Link to item Cite

Quality Control Practices for Chemistry and Immunochemistry in a Cohort of 21 Large Academic Medical Centers.

Journal Article Am J Clin Pathol · July 3, 2018 OBJECTIVES: In the United States, minimum standards for quality control (QC) are specified in federal law under the Clinical Laboratory Improvement Amendment and its revisions. Beyond meeting this required standard, laboratories have flexibility to determi ... Full text Link to item Cite

Relationships and Clinical Utility of Creatinine, Cystatin C, eGFRs, GFRs, and Clearances.

Journal Article J Appl Lab Med · November 1, 2017 BACKGROUND: This review addresses techniques for glomerular filtration rate (GFR), either measured by clearance tests such as with creatinine, iothalamate, inulin, or iohexol [measured GFR (mGFR)] or calculated by equations that determine the estimated GFR ... Full text Link to item Cite

The analytical change in plasma creatinine that constitutes a biologic/physiologic change.

Journal Article Clin Chim Acta · August 1, 2016 PURPOSE: Accurate and precise measurements of creatinine are necessary to evaluate changes in kidney function related to a decreased glomerular filtration rate (GFR). When serial measurements of creatinine are monitored in an individual, it is useful to kn ... Full text Link to item Cite

Monitoring Oxygen Status.

Journal Article Adv Clin Chem · 2016 Although part of a common "blood gas" test panel with pH and pCO2, the pO2, %O2Hb, and related parameters are independently used to detect and monitor oxygen deficits from a variety of causes. Measurement of blood gases and cooximetry may be done by labora ... Full text Link to item Cite

Performance Evaluation of a Glucose Monitoring System for Point-of-Care Testing with the Critically Ill Patient Population - A Multicenter Study

Journal Article Point of Care · March 11, 2015 To evaluate the performance of the ACCU-CHEK Inform II glucose meter system for use in critically ill patients, and to assess the effects of blood oxygen tension, hematocrit, sodium levels on glucose measurements. A multicenter study involving the collecti ... Full text Cite

Clinical evaluation of the FreeStyle Precision Pro system.

Journal Article Clin Chim Acta · June 5, 2013 BACKGROUND: A new version of international standard (ISO 15197) and CLSI Guideline (POCT12) with more stringent accuracy criteria are near publication. We evaluated the glucose test performance of the FreeStyle Precision Pro system, a new blood glucose mon ... Full text Link to item Cite

Clarifying the fog of natural and manmade renal function tests: Creatinine, clearances, glomerular filtration rate, and estimated glomerular filtration rate

Journal Article Point of Care · March 1, 2011 This review addresses common misconceptions about serum creatinine, glomerular filtration rate (GFR) measured by either clearance tests (creatinine, iothalamate, inulin, etc) or by equations that calculate the estimated GFR (eGFR), the perceived benefit of ... Full text Cite

Improving the clinical value of estimating glomerular filtration rate by reporting all values: a contrarian viewpoint.

Journal Article Nephron Clin Pract · 2010 Featured Publication The serious limitations of the estimating glomerular filtration rate (eGFR) appear related not to a shortcoming of the equation, but to the futility of trying to force agreement between two inherently different parameters: a blood marker of kidney function ... Full text Link to item Cite

Comparison of Creatinine, Urea, Ionized Calcium, and Bicarbonate Methods by 2 POC Systems and a Mainframe Chemistry Analyzer.

Journal Article J Appl Lab Med · March 6, 2023 BACKGROUND: The i-STAT (iST) and GEM Premier ChemSTAT (ChmST) are point-of-care systems that measure electrolytes, metabolites, acid-base parameters, and hematocrit on blood. We compared results for creatinine, urea (blood urea nitrogen [BUN]), total carbo ... Full text Link to item Cite

Evaluating the Association Between Fibrinogen and Rotational Thromboelastometry and the Progression to Severe Obstetric Hemorrhage.

Journal Article Clin Appl Thromb Hemost · 2023 AIM: This study aims to investigate the ability of fibrinogen and rotational thromboelastometry (ROTEM) parameters measured at obstetric hemorrhage protocol initiation to predict severe hemorrhage. METHODS: In this retrospective study we included patients ... Full text Link to item Cite

Retrospective Analysis of Quality Control Data Using Pooled Blood to Compare Agreement within Two Models of Blood Gas Analyzers.

Journal Article J Appl Lab Med · September 1, 2021 BACKGROUND: Two previous reports from the same group concluded that the analytical reliability of Instrumentation Laboratory GEM4000 analyzers (GEM4K) deteriorated during a 24-hour period, based on results between samples from the same patient but collecte ... Full text Link to item Cite

Blood Gases and Critical Care Testing: Physiology, Clinical Interpretations, and Laboratory Applications

Book · January 1, 2021 Blood gas tests are a group of tests that are widely used and essential for the evaluation and management of a patient’s ventilation, oxygenation, and acid-base balance, often in emergent situations, and along with blood gases are other critical care analy ... Full text Cite

Using α-Angle and A10 ROTEM Parameters for Earlier Information on Clotting Status in Surgery, Postpartum Hemorrhage, and ICU Patients

Journal Article Point of Care · June 1, 2019 Background We determined if the earlier ROTEM (rotational thromboelastometry) parameters (α-angle and amplitude at 10 minutes [A10]) could replace the later-reported maximum amplitude (maximum clot firmness [MCF]) in cardiothoracic surgery (C/T OR), postpa ... Full text Cite

Use of Earlier-Reported Rotational Thromboelastometry Parameters to Evaluate Clotting Status, Fibrinogen, and Platelet Activities in Postpartum Hemorrhage Compared to Surgery and Intensive Care Patients.

Journal Article Anesth Analg · March 2019 BACKGROUND: Rotational thromboelastometry (ROTEM) can provide clinical information in 10-20 minutes for guiding administration of fibrinogen, platelets, and fresh frozen plasma products. While ROTEM testing is well established for cardiac and other surgeri ... Full text Link to item Cite

Effect of beef ingestion by humans on plasma concentrations of creatinine, urea, and cystatin C.

Journal Article Clin Biochem · August 2018 PURPOSE: The effect of eating meat on serum concentrations of creatinine has varied among previous reports, with some finding no effect and others finding 50-100% increases, which appears related to how the beef is cooked. For other analytes related to kid ... Full text Link to item Cite

Quality Control Practices for Chemistry and Immunochemistry in a Cohort of 21 Large Academic Medical Centers.

Journal Article Am J Clin Pathol · July 3, 2018 OBJECTIVES: In the United States, minimum standards for quality control (QC) are specified in federal law under the Clinical Laboratory Improvement Amendment and its revisions. Beyond meeting this required standard, laboratories have flexibility to determi ... Full text Link to item Cite

Relationships and Clinical Utility of Creatinine, Cystatin C, eGFRs, GFRs, and Clearances.

Journal Article J Appl Lab Med · November 1, 2017 BACKGROUND: This review addresses techniques for glomerular filtration rate (GFR), either measured by clearance tests such as with creatinine, iothalamate, inulin, or iohexol [measured GFR (mGFR)] or calculated by equations that determine the estimated GFR ... Full text Link to item Cite

The analytical change in plasma creatinine that constitutes a biologic/physiologic change.

Journal Article Clin Chim Acta · August 1, 2016 PURPOSE: Accurate and precise measurements of creatinine are necessary to evaluate changes in kidney function related to a decreased glomerular filtration rate (GFR). When serial measurements of creatinine are monitored in an individual, it is useful to kn ... Full text Link to item Cite

Monitoring Oxygen Status.

Journal Article Adv Clin Chem · 2016 Although part of a common "blood gas" test panel with pH and pCO2, the pO2, %O2Hb, and related parameters are independently used to detect and monitor oxygen deficits from a variety of causes. Measurement of blood gases and cooximetry may be done by labora ... Full text Link to item Cite

Performance Evaluation of a Glucose Monitoring System for Point-of-Care Testing with the Critically Ill Patient Population - A Multicenter Study

Journal Article Point of Care · March 11, 2015 To evaluate the performance of the ACCU-CHEK Inform II glucose meter system for use in critically ill patients, and to assess the effects of blood oxygen tension, hematocrit, sodium levels on glucose measurements. A multicenter study involving the collecti ... Full text Cite

Clinical evaluation of the FreeStyle Precision Pro system.

Journal Article Clin Chim Acta · June 5, 2013 BACKGROUND: A new version of international standard (ISO 15197) and CLSI Guideline (POCT12) with more stringent accuracy criteria are near publication. We evaluated the glucose test performance of the FreeStyle Precision Pro system, a new blood glucose mon ... Full text Link to item Cite

Clarifying the fog of natural and manmade renal function tests: Creatinine, clearances, glomerular filtration rate, and estimated glomerular filtration rate

Journal Article Point of Care · March 1, 2011 This review addresses common misconceptions about serum creatinine, glomerular filtration rate (GFR) measured by either clearance tests (creatinine, iothalamate, inulin, etc) or by equations that calculate the estimated GFR (eGFR), the perceived benefit of ... Full text Cite

Improving the clinical value of estimating glomerular filtration rate by reporting all values: a contrarian viewpoint.

Journal Article Nephron Clin Pract · 2010 Featured Publication The serious limitations of the estimating glomerular filtration rate (eGFR) appear related not to a shortcoming of the equation, but to the futility of trying to force agreement between two inherently different parameters: a blood marker of kidney function ... Full text Link to item Cite

Variation of serum creatinine, cystatin C, and creatinine clearance tests in persons with normal renal function.

Journal Article Clin Chim Acta · September 2008 Featured Publication BACKGROUND: To determine the potential sensitivity of several renal function tests for detecting early changes in renal function, we compared the within-individual (W-I) variation over 5 months of serum creatinine, serum cystatin C, and creatinine clearanc ... Full text Link to item Cite

Misconceptions in reporting oxygen saturation.

Journal Article Anesth Analg · December 2007 BACKGROUND: We describe some misconceptions that have become common practice in reporting blood gas and cooximetry results. In 1980, oxygen saturation was incorrectly redefined in a report of a new instrument for analysis of hemoglobin (Hb) derivatives. Ox ... Full text Link to item Cite

Validation of a quality assessment system for blood gas and electrolyte testing.

Journal Article Clin Chim Acta · July 2007 BACKGROUND: A recently-introduced quality assessment system (Intelligent Quality Management: iQM), was evaluated in routine clinical use at four different hospitals. The iQM technology is designed to replace conventional external liquid controls with softw ... Full text Link to item Cite

Controlling magnesium in surgery, intensive care, and beyond

Journal Article Point of Care · June 1, 2007 In addition to the biochemical and physiological importance of magnesium, the increasing number of conditions associated with magnesium depletion, such as drug therapy and stress from surgery or trauma, have contributed toward increasing the clinical impor ... Full text Cite

Changing systems for measuring activated clotting times: impact on the clinical practice of heparin anticoagulation during cardiac surgery.

Journal Article Clin Chim Acta · June 2005 Featured Publication BACKGROUND: The activated clotting time (ACT) is a standard monitor for heparin anticoagulation during cardiopulmonary bypass (CPB). This study determines the effect of upgrading our ACT system on our clinical practice with regards to the conduct and safet ... Full text Link to item Cite

The relationship between ionized and total serum magnesium concentrations during abdominal surgery.

Journal Article J Clin Anesth · June 2003 Featured Publication STUDY OBJECTIVE: To determine the necessity for ionized magnesium (iMg) assay by evaluating the effect of abdominal surgery without massive transfusion on total magnesium (Mg) and iMg concentrations. DESIGN: Prospective, observational study. SETTING: Opera ... Full text Link to item Cite

Implementing a New Method for Activated Clotting Time

Journal Article Plastic Surgical Nursing · January 1, 2003 Point-of-care determination of the activated clotting time (ACT) has become the standard of care in a number of clinical situations. The authors converted from ACT done by the Hemochron 801 analyzer, which uses tubes containing either celite, kaolin, or gl ... Full text Cite

Multicenter Study on the Analytical Performance of a New Point-of-Care Blood Gas Analyzer

Journal Article Plastic Surgical Nursing · January 1, 2003 A multicenter study was carried out to investigate the analytical performance characteristics of the new blood gas analyzer, Roche OMNI C, in a clinical setting. In method comparison experiments, all results with Roche OMNI C were at least in good agreemen ... Full text Cite

pH effects on measurements of ionized calcium and ionized magnesium in blood.

Journal Article Arch Pathol Lab Med · August 2002 Featured Publication CONTEXT: It is well known that the concentration of ionized calcium in blood is affected by the pH of the specimen, since hydrogen ions compete with calcium for binding sites on albumin and other proteins. However, the relationship between pH and ionized m ... Full text Link to item Cite

Activated clotting time systems vary in precision and bias and are not interchangeable when following heparin management protocols during cardiopulmonary bypass.

Journal Article J Clin Monit Comput · July 2002 OBJECTIVE: Our aim was to test the hypothesis that new activated clotting time (ACT) technology, with modifications to instruments and reagents designed to detect earlier clot formation, would be associated with more precise but lower results. A secondary ... Full text Link to item Cite

Blood glucose meter performance under hyperbaric oxygen conditions.

Journal Article Clin Chim Acta · March 2001 This study evaluated the accuracy of the Precision PCx (PCx) against another bedside blood glucose meter SureStepPro (SSP), which has been shown to be unaffected by high P(O(2)). Human blood samples were used to prepare plasma glucose (PG) concentrations o ... Full text Link to item Cite

The effects of heparin anticoagulants and fill volume in blood gas syringes on ionized calcium and magnesium measurements.

Journal Article Clin Chim Acta · February 2001 We studied the effects of several heparin anticoagulants on ionized calcium and ionized magnesium measurements. Venous blood from 24 healthy donors was drawn into 20-ml syringes without an anticoagulant, and immediately analyzed for control results. They w ... Full text Link to item Cite

Measurement of plasma glucose under hyperbaric oxygen conditions

Journal Article South Pacific Underwater Medicine Society Journal · December 1, 2000 This study was designed to evaluate the accuracy of the bedside glucometer SureStepPro (SSP, LifeScan Inc; Milpitas, California) against a standard laboratory instrument (Yellow Springs Instruments [YSI] 2300 STAT PLUS; Yellow Springs, Ohio) during hyperba ... Cite

Wireless POCT data transmission.

Journal Article MLO: medical laboratory observer · January 1, 2000 Despite the many advantages of POCT, the biggest obstacle for the lab often becomes documentation and billing of tests performed at remote locations. To solve this problem, this lab took advantage of a wireless radiofrequency network that had been installe ... Cite

Blood gas testing in the laboratory and at the point of care. Finding the right mix.

Journal Article MLO: medical laboratory observer · January 1, 1997 Cite

Pneumatic transport exacerbates interference of room air contamination in blood gas samples.

Journal Article Arch Pathol Lab Med · July 1996 Featured Publication OBJECTIVE: To characterize and control the potential interference to P(O2) determinations when blood contaminated with air is sent via a pneumatic tube system (PTS). DESIGN: Both tonometered blood at P(O2)s of 65, 75, 142, and 339 mm Hg and arterial blood ... Link to item Cite

Evaluation of the YSI 2300 glucose analyzer: algorithm-corrected results are accurate and specific.

Journal Article Clin Biochem · February 1996 OBJECTIVES: To insure commutability (equivalence) between whole blood and plasma glucose values and to assess potential interferences in glucose oxidase methods. DESIGN AND METHODS: We compared plasma glucose results by the Ektachem 700 analyzer to glucose ... Full text Link to item Cite

Elevations in blood lactate: overview of use in critical care.

Journal Article Scand J Clin Lab Invest Suppl · 1996 Blood lactate measurements are being used clinically as an indicator of circulatory impairment and the overall state of oxygenation of patients in critical care. This report briefly covers the areas of usage of lactate testing, lactate biochemistry, approp ... Full text Link to item Cite

Physiology and regulation. Ionized calcium, magnesium and lactate measurements in critical care settings.

Journal Article Am J Clin Pathol · October 1995 The biochemical and physiologic bases for clinical use of ionized calcium, magnesium, or lactate measurements are described, with emphasis on the critical care setting. Ionized calcium or magnesium are usually measured to prevent hypocalcemia or hypomagnes ... Link to item Cite

Interpretation of blood lactate measurements in paediatric open-heart surgery and in extracorporeal membrane oxygenation.

Journal Article Scand J Clin Lab Invest · July 1995 For the purpose of demonstrating both the clinical value and economic advantages of using blood lactate as a marker for haemodynamic instability, we present the clinical guidelines for when to measure blood lactate and how these measurements are interprete ... Full text Link to item Cite

Determination of potassium by dry reagent carrier technology: a multicentre evaluation.

Journal Article Eur J Clin Chem Clin Biochem · August 1993 We describe the construction, the reaction principle and the performance of Reflotron K+, a new Reflotron test for the quantitative determination of potassium in serum and heparinized plasma. The reaction principle is based on the introduction of the potas ... Full text Link to item Cite

Lactate measured in diluted and undiluted whole blood and plasma: comparison of methods and effect of hematocrit.

Journal Article Clin Chem · December 1992 We evaluated a new analyzer that measures lactate in undiluted whole blood by direct (or undiluted) amperometry [Nova Stat Profile 7 Analyzer (SP7); Nova Biomedical, Waltham, MA] by comparing it with two other analyzers, one for measuring lactate in whole ... Link to item Cite

Dry electrolyte-balanced heparinized syringes evaluated for determining ionized calcium and other electrolytes in whole blood.

Journal Article Clin Chem · October 1991 By analyzing whole blood containing no anticoagulants (uncoagulated whole blood) immediately after collection, we evaluated the relative changes in the concentrations of ionized calcium and other electrolytes in whole blood collected in dry heparinized syr ... Link to item Cite

The response of parathyroid hormone to specific changes in either ionized calcium, ionized magnesium, or protein-bound calcium in humans.

Journal Article Metabolism · August 1991 Because the effects of specific changes in magnesium or protein-bound calcium on biologic processes in humans have not been clearly defined, we developed an experimental system to specifically lower either ionized calcium, protein-bound calcium, or ionized ... Full text Link to item Cite

Clinical chemistry.

Journal Article Anal Chem · June 15, 1991 Full text Link to item Cite

Blood lactate: biochemistry, laboratory methods, and clinical interpretation.

Journal Article Crit Rev Clin Lab Sci · 1991 With the renewed awareness of blood lactate as an indicator of circulatory impairment, there has been much interest in the use of lactate measurements to determine the overall state of oxygenation of patients in critical care. This review begins by coverin ... Full text Link to item Cite

Relative increase in creatine kinase MB isoenzyme during reperfusion after myocardial infarction is method dependent

Journal Article Clinical Chemistry · January 1, 1990 We compared relative increases in creatine kinase (EC 2.7.3.2) MB isoenzyme (CK-MB) after reperfusion in myocardial infarction for four popular methods: electrophoresis, immunoinhibition, the "Magic Lite" (Ciba-Corning) system, and the Stratus (Dade). In a ... Cite

Characteristics of creatine kinase-MB and MB isoforms in serum after reperfusion in acute myocardial infarction.

Journal Article Clin Chem · November 1989 Characteristics of CK-MB, the MB1 and MB2 isoforms, and the MB2/MB1 ratio are described in six acute myocardial infarction (AMI) patients in whom the infarct-related artery was identified and, after intervention, normal coronary flow was re-established. Af ... Link to item Cite

Effects of in vivo and in vitro production of lactic acid on ionized, protein-bound, and complex-bound calcium in blood.

Journal Article Clin Chem · June 1989 We have studied, both in vitro and in vivo, the quantitative effects of lactic acid production on concentrations of ionized calcium, bound calcium, pH, bicarbonate, and albumin. To do so, we examined the effects of addition of aqueous solutions of either h ... Link to item Cite

Plasma levels of ionized and total calcium during storage of citrated platelet concentrate

Journal Article Transfusion · 1989 Measurements of ionized and total calcium levels in supernatant plasma samples from citrated platelet concentrates (PCs) were made over 7 days of storage. Both ionized and total calcium increased significantly during the storage period: respectively, from ... Cite

Clinical validation of an automated thin-film reflectance method for measurement of magnesium in serum and urine.

Journal Article Magnesium · 1988 We evaluated an automated method for measuring total magnesium in serum, plasma, or urine that utilizes dry multilayered thin-film reagents and reflectance photometry for use on the Kodak Ektachem 400 analyzer. Comparison of magnesium results by this metho ... Link to item Cite

Relationship between serum lactate and ionized calcium in open-heart surgery.

Journal Article Clin Chem · October 1986 We studied 16 patients undergoing open-heart surgery and heart-lung bypass, to examine the relationship between ionized calcium and lactate. Blood was sampled at successive stages of the operation for measurement of ionized and total calcium, lactate, bloo ... Link to item Cite

Aqueous and serum-based materials compared for use as simulated calibrators for three ionized calcium analyzers.

Journal Article Clin Chem · August 1986 To determine if bias between different ionized calcium analyzers could be decreased, we analyzed 10 control fluids during a study in which ionized calcium was measured in more than 150 serum and whole-blood samples. After calibrating three ionized calcium ... Link to item Cite

Chemistry analyzers for the physician's office

Journal Article Pathologist · January 1, 1986 Several new clinical chemistry analyzers may be operated on a desk top and need only an electrical connection for operation. Many of their features make them well-suited to in-office testing. Data about their cost, throughput, and operation are provided, a ... Cite

Preparation and use of serum-based material as control and calibrator in evaluating ion-selective electrodes for calcium.

Journal Article Clin Chem · August 1985 We analyzed 93 sera and 81 whole-blood samples, plus several aqueous materials and one serum-based material as controls, with two analyzers for ionized calcium (Radiometer ICA 1 and AVL 980). On 16 days, comparisons of results for patients' samples were go ... Link to item Cite

Influence of continuous infusion of citrate on responses of immunoreactive parathyroid hormone, calcium and magnesium components, and other electrolytes in normal adults during plateletapheresis.

Journal Article J Clin Endocrinol Metab · May 1985 To study the relationships between changes in concentrations of different forms of calcium and the responses of immunoreactive PTH in humans during citrate-induced hypocalcemia, we studied 12 healthy donors undergoing continuous flow plateletapheresis. Con ... Full text Link to item Cite

Analytical aspects and clinical applications of ionized calcium measurements

Journal Article Health Care Instrumentation · January 1, 1985 Cite

Effects of storage temperature and time before centrifugation on ionized calcium in blood collected in plain vacutainer tubes and silicone-separator (SST) tubes.

Journal Article Clin Chem · April 1984 We studied the stability of ionized calcium and pH in samples stored at either room temperature or 4 degrees C, in centrifuged and uncentrifuged blood-collection tubes and in centrifuged tubes containing a silicone-separator gel (SST tubes). At room temper ... Link to item Cite

Total, ultrafiltrable, dialysable and ionised calcium measurements in randomly selected samples compared with clinical diagnoses.

Journal Article Ann Clin Biochem · November 1983 Total, ultrafiltrable (Worthington 'Ultrafree'), dialysable and ionised (Orion SS-20) calcium levels were measured in 110 serum samples selected randomly from patients for whom total calcium was ordered as a routine test. The available medical records were ... Full text Link to item Cite

An automated dry-slide enzymatic method evaluated for measurement of creatinine in serum.

Journal Article Clin Chem · April 1983 We evaluated an automated dry-slide enzymatic method involving creatinine iminohydrolase for measurement of creatinine in serum with the Kodak Ektachem analyzer. The means (and SD) for three commercially available quality-control sera, analyzed during eigh ... Link to item Cite

Changes in protein-bound, complex-bound, and ionized calcium related to parathyroid hormone levels in healthy donors during plateletapheresis.

Journal Article Transfusion · 1983 In order to relate changes in protein-bound and complex-bound calcium to levels of citrate and secretion of parathyroid hormone during mild hypocalcemia, total, ultrafiltrable, and ionized calcium were measured in 13 apparently healthy donors during platel ... Full text Link to item Cite

Enzymic determination of citrate in serum and urine, with use of the Worthington "ultrafree" device.

Journal Article Clin Chem · January 1982 We describe an enzymic method for conveniently measuring citrate in serum or urine. Interfering enzyme proteins are removed by a disposable ultrafilter ("Ultrafree"; Worthington Diagnostics), obviating the need for hazardous protein precipitants. A 50 mmol ... Link to item Cite

The Worthington "ultrafree" device evaluated for determination of ultrafiltrable calcium in serum.

Journal Article Clin Chem · March 1981 We evaluated a commercially-available disposable device ("Ultrafree," Worthington Diagnostics) for the anaerobic preparation of protein-free ultrafiltrates from serum for measurement of ultrafiltrable calcium. Sufficient filtrate for the analysis is obtain ... Link to item Cite

Spectrophotometric micro method for measurement of dialyzable calcium by use of cresolphthalein complexone and continuous-flow analysis.

Journal Article Clin Chem · October 1980 We adapted a method for dialyzable calcium from fluorometric detection by use of calcein to a more specific spectrophotometric determination with cresolphthalein complexone. The reagents are available commercially and perform satisfactorily with respect to ... Link to item Cite

Improvements in and clinical utility of a continuous-flow method for routine measurement of dialyzable (ultrafiltrable) calcium.

Journal Article Clin Chem · November 1979 We describe modifications to the original continuous-flow procedure for dialyzable calcium (Clin. Chem. 23: 1258, 1977) needed to make the method more suitable for routine clinical laboratory use. The modifications simplify the continuous-flow (AutoAnalyze ... Link to item Cite

Increase in dialyzable calcium associated with therapy with lithium.

Journal Article Clin Chem · October 1979 We measured total and dialyzable calcium concentrations in consecutive sera submitted for routine lithium analysis. Of 98 samples from 61 different individuals, six (6.1%) total calcium results and 32 (33%) dialyzable calcium results were above the respect ... Link to item Cite

Use of gel filtration to examine the distribution of calcium among serum proteins.

Journal Article Clin Chem · December 1977 Gel filtration of serum by use of dextran bisacrylamide beads ("Sephacryl S-200," fractionation range: 5000-250 000 daltons), separates the serum proteins into three distinct peaks. We used an eluent containing (per liter) 140 mmol of sodium, 1.10 mmol of ... Link to item Cite

Continuous-flow determination of dialyzable calcium in serum.

Journal Article Clin Chem · July 1977 We describe a procedure for measuring dialyzable calcium in 60 sera per hour with use of AutoAnalyzer (Technicon) modules. The serum is buffered, then dialyzed in a regular 6-inch (15-cm) dialysis block. A constant proportion of the dialyzable calcium is f ... Link to item Cite

Separation and quantitation of serum constituents associated with calcium by gel filtration.

Journal Article Clin Chem · December 1976 Gel filtration of serum by use of polyacrylamide beads (Biogel P-2) separates total colcium into four distinct peaks: an initial peak, corresponding to protein-bound calcium; a second peak containing the calcium complexes of citrate, phosphate, lactate, an ... Link to item Cite

An overview of the laboratory diagnosis of lead poisoning.

Journal Article Ann Clin Lab Sci · 1976 Four tests for the evaluation of lead poisoning are reviewed from both the clinical and methodological aspects. Whole blood or erythrocyte lead measurements appear to provide the best means of assessing the bodily burden of lead with electrothermal and Del ... Link to item Cite