scholarly journals Calcium Measurement

2020 ◽  
Author(s):  
Keyword(s):  
Calcium Measurement

scholarly journals Parathormone stability in hemodialyzed patients and healthy subjects: comparison on non-centrifuged EDTA and serum samples with second- and third-generation assays

2017 ◽  
Vol 55 (8) ◽  
pp. 1152-1159 ◽  
Author(s):  
Marie-Louise Schleck ◽  
Jean-Claude Souberbielle ◽  
Pierre Delanaye ◽  
Mario Plebani ◽  
Etienne Cavalier
Keyword(s):  
Healthy Subjects ◽  
Room Temperature ◽  
Wilcoxon Test ◽  
Dialysis Session ◽  
Third Generation ◽  
Serum Samples ◽  
Total Change ◽  
Edta Plasma ◽  
Calcium Measurement ◽  
Single Batch

Abstract Background: Parathyroid hormone (PTH) stability is important. Many studies have shown divergent results between EDTA and serum, which are mainly linked to differences in protocols or cut-offs used to determine whether or not PTH remained stable. No studies have yet compared PTH stability as measured by second- and third-generation assays on the same samples in hemodialyzed patients and healthy subjects. Methods: Five pairs of samples (EDTA and gel tubes) were obtained in 10 hemodialyzed patients before a dialysis session and in 10 healthy subjects. One pair was centrifuged and run directly to define the “T0”. Two pairs were kept at +4°C and two pairs were kept at +25°C. They were centrifuged after 4 and 18 h. Supernatant was kept at –80°C for 1 week. All samples were measured in a single batch, on Roche Cobas and DiaSorin XL second- and third-generation PTH assays. We used three different approaches to evaluate PTH stability: Wilcoxon test, an Acceptable Change Limit (ACL) according to ISO Guide 5725-6 and a Total Change Limit (TCL) derived from the sum of biological and technical variability according to WHO. Results: PTH decreased in all samples. Stability of PTH was mainly dependent on the way it was evaluated. Percentages of decrease were systematically lower in EDTA vs. serum. Wilcoxon and ACL showed that PTH was no more stable after 4 h at +4°C in EDTA or serum gel tubes. None of the subjects presented a PTH decrease higher than the TCL with EDTA plasma. In serum gel tubes, PTH was unstable only when kept at 25°C for 18 h. Conclusions: PTH seems more stable in EDTA than in serum gel tubes but only when samples have to stay unprocessed for a long period (18 h) at room temperature (25°C), which can happen when samples are delivered from external care centers. For all the other conditions, using serum gel tubes is recommended since calcium measurement, which is necessary for a good PTH results interpretation, can be achieved on the same tube.

Postanalytical Quality Improvement

2000 ◽  
Vol 124 (4) ◽  
pp. 504-510 ◽  
Author(s):  
Peter J. Howanitz ◽  
George S. Cembrowski
Keyword(s):  
Quality Improvement ◽  
Medical Records ◽  
Laboratory Tests ◽  
Reference Range ◽  
Physician Practices ◽  
New Finding ◽  
Analytical Step ◽  
New Diagnosis ◽  
Calcium Measurement

Abstract Objective.—To evaluate elevated patient calcium results as a postanalytic quality indicator of physician practices. Design.—Participants prospectively identified hypercalcemic patient results for 4 months or until they found 320 hypercalcemic results, and then, after at least 3 days, reviewed the medical records of these patients. Hypercalcemia was defined as a calcium value that exceeded the upper limit of each laboratory's reference range by 0.12 mmol/L or more. Participants, as well a subset of their physicians who did not acknowledge or respond to elevated results in the medical record, answered a questionnaire about their practices. Participants.—Five hundred twenty-five laboratories enrolled in the College of American Pathologists Q-Probes program. Main Outcome Measures.—The presence of hyercalcemic results in patients' medical records and physicians' acknowledgement and response to those elevated results. Results.—More than 5500 hypercalcemic results were identified, of which 53.2% represented a new finding. About 3.5% of results were not charted in the patients' records, and 23.1% of patient records did not contain clinician documentation of the abnormal result. Follow-up laboratory tests were not ordered for 13.8% of the elevated values. For 570 of the 808 results for which there was neither clinician documentation nor designated follow-up laboratory tests ordered, patients' physicians received written notification of the elevated calcium results along with a questionnaire. Responses were received from 386 physicians (68%). One hundred physicians indicated they did not order the specific calcium measurement, and of these 100, 85 responded it was part of a panel. The 286 physicians who ordered the test stated the results ultimately led to further testing (69%), a change of management (56%), or a new diagnosis (25%). Conclusions.—We found that a high percentage of abnormal results (3.5%) were not documented in the patients' medical records, the diagnosis of hypercalcemia frequently was new (53.2%), and a high percentage of physicians did not respond to elevated calcium results by writing a note (23.1%) or ordering another test (13.8%). Opportunities for quality improvement at these postanalytical steps are far greater than at the analytical step. Laboratorians must help physicians identify and respond to clinically important laboratory results.

scholarly journals Intracellular calcium measurement in isolated rat arterioles during phasic and tonic contractions

1992 ◽  
Vol 58 ◽  
pp. 367
Author(s):  
Akihiko Karibe ◽  
Mitsumasa Keitoku ◽  
Jun Watanabe ◽  
Tamotsu Takishima
Keyword(s):  
Intracellular Calcium ◽  
Calcium Measurement ◽  
Isolated Rat

scholarly journals Reducing Routine Ionized Calcium Measurement

2009 ◽  
Vol 55 (3) ◽  
pp. 533-540 ◽  
Author(s):  
Geoffrey S Baird ◽  
Petrie M Rainey ◽  
Mark Wener ◽  
Wayne Chandler
Keyword(s):  
Calcium Supplementation ◽  
Reference Interval ◽  
Ionized Calcium ◽  
Total Calcium ◽  
Calcium Treatment ◽  
Testing Strategy ◽  
Substantial Fraction ◽  
Oral Calcium ◽  
Testing Frequency ◽  
Calcium Measurement

Abstract Background: Ionized calcium (iCa) is measured frequently in hospitalized patients, and hypocalcemia is frequently found, seemingly supporting the practice. Methods: We retrieved the results of 58 040 iCa tests and records of intravenous (IV) and oral calcium supplementation from laboratory and hospital information systems and evaluated them for frequency of testing, frequency of hypocalcemia, and effects of calcium supplementation. Results: Serial and daily iCa testing was common and responsible for a substantial fraction of all iCa tests ordered. Half of all patients tested had iCa values below the reference interval. IV, but not oral, calcium therapy increased mean iCa concentrations, but the effect of calcium administration was small compared with the spontaneous increase in iCa that occurred in similar patients who received no calcium treatment. A retrospective analysis suggested that a low total calcium (tCa) concentration (<2.00 mmol/L, <8 mg/dL) could identify most patients with low iCa (<1.0 mmol/L). Introduction of a reflexive strategy reduced iCa testing by 72%–76% and reduced IV calcium gluconate therapy by 45%–81%. Conclusions: Testing for iCa and IV calcium supplementation were significantly reduced with a reflexive calcium testing strategy that provided iCa testing only to patients with low tCa. Adverse clinical outcomes possibly associated with hypocalcemia did not increase.

scholarly journals Study of the incidence of hypocalcemia in patients undergoing bilateral thyroid surgery

2020 ◽  
Vol 7 (9) ◽  
pp. 2914
Author(s):  
Baleshwar Dhiman ◽  
Satish Dalal ◽  
Nityasha Dalal ◽  
Sethu Raman
Keyword(s):  
Serum Calcium ◽  
Thyroid Surgery ◽  
Thyroid Disease ◽  
Study Data ◽  
P Value ◽  
Chi Square ◽  
Ethical Approval ◽  
Chi Square Test ◽  
Calcium Measurement ◽  
Benign Thyroid

Background: Thyroid surgery are among the most common operations performed all over the world. Hypocalcemia following total thyroidectomy is a fairly common complication. Occurrence of acute hypocalcemia can be predicted in patients undergoing thyroid surgery, based on serial calcium measurement and this helps in early prediction of hypocalcemia. The aim of present study was to assess the incidence of post thyroidectomy hypocalcemia and factors which might play a role in its occurrence.Methods: A total 30 patients who underwent bilateral thyroidectomy were analysed. The study period was from June 2017 to March 2019. The incidence of hypocalcemia was analysed with serial calcium estimation in immediate post-operative period, 4 hours and 24 hours after surgery and on 5th post-operative day. The factors analysed included pre-operative and post-operative serum calcium levels, clinical features, the disease type and factors related to surgery. The ethical approval was taken from the ethical committee of the institute. At the end of the study data was collected and analysed by using student t-test and chi square test. A p-value of less than 0.05 was considered significant.Results: Post-operative transient hypocalcemia developed in 21 patients out of 30 (70%). Of them six patients (28.75%) developed severe hypocalcemia and 15 (71.42%) developed mild to moderate hypocalcemia. Out of six patients, five patients were histopathologically diagnosed as malignant thyroid disease. 15 patients who developed mild to moderate hypocalcemia were diagnosed to be having benign thyroid conditions.Conclusions: Patients underwent thyroid surgery for malignant conditions showed higher incidence and severity hypocalcemia as compared to cases where surgery was performed for benign thyroid disease. This complication can be prevented with meticulous perioperative dissection, prompt identification of parathyroid glands and frequent postoperative monitoring of serum calcium levels.

Artifacts in calcium measurement: recognition and remedies

1991 ◽  
Vol 1 (2-3) ◽  
pp. 71-74 ◽  
Author(s):  
Stephen Bolsover ◽  
R. Angus Silver
Keyword(s):  
Calcium Measurement

Spurious Hypocalcemia After Omniscan- or OptiMARK-Enhanced Magnetic Resonance Imaging: An Algorithm for Minimizing a False-Positive Laboratory Value

2004 ◽  
Vol 128 (10) ◽  
pp. 1151-1156
Author(s):  
Jane Emerson ◽  
Gerald Kost
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Contrast Agents ◽  
Calcium Level ◽  
Gadopentetate Dimeglumine ◽  
Total Calcium ◽  
Resonance Imaging ◽  
Contrast Enhanced ◽  
Calcium Measurement

Abstract Contrast-enhanced magnetic resonance imaging has become a routine diagnostic imaging procedure. Reports in the literature document that 2 of the 4 available gadolinium-based magnetic resonance imaging contrast agents, gadodiamide (Omniscan) and gadoversetamide (OptiMARK), are less stable and readily undergo dechelation. In vitro, this dechelation can result in interference with the most common laboratory methods used to measure total plasma or serum calcium. The result of total calcium measurement soon after contrast-enhanced magnetic resonance imaging with these interfering contrast agents is a spurious lowering of the total calcium level. This low calcium measurement may result in a value consistent with hypocalcemia and can persist in patients with renal insufficiency and in patients receiving higher doses of contrast agent. Alternatively, a clinically significant elevated calcium level may be overlooked because of the artificially lowered value. Two of the available gadolinium-based contrast agents, gadoteridol (ProHance) and gadopentetate dimeglumine (Magnevist), have not been to shown to interfere with total calcium measurement. A clinical practice algorithm for the laboratorian, the radiologist, and the clinician is presented to minimize the occurrence and consequences of a spuriously lowered total calcium level due to Omniscan- or OptiMARK-enhanced magnetic resonance imaging.

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