Pseudohypocalcemia in Cancer Patients: A Recommendation for the Postanalytical Correction of Serum Calcium in Patients with Hypoalbuminemia

Clinical and epidemiologic characteristics of hospitalized oncological patients with hypercalcemia: a longitudinal, multicenter study

BACKGROUND

There are few studies that have analyzed the characteristics of hypercalcemia in hospitalized oncological patients. Our objectives were to describe the clinical characteristics of hospitalized patients with paraneoplastic hypercalcemia and to identify prognostic variables for mortality.

METHODS

This was an observational, longitudinal, retrospective, and bicentric study. It included adult patients admitted to two hospitals in Málaga, Spain (2014-2018). The minimum follow-up period was 2 years or until death.

RESULTS

A total of 154 patients were included; the majority (71.4%) were admitted to the internal medicine department. The median follow-up was 3.5 weeks (interquartile range [IQR] 1.1-11.5). The mean (standard deviation) age was 67.6 (12.3) years, with a predominance of males (58.4%). The median (IQR) serum calcium at admission was 13.2 (11.8-14.6) mg/dl. The most common neoplasms were pulmonary (27.3%), hematologic (23.4%), urological (13%), and breast (12.3%). Furthermore, 56.5% of cases had a known history of neoplasia at the time of diagnosis. The parathyroid hormone (PTH) level was determined in 24%; of these, 10.8% had elevated levels. In all, 95.5% of patients died during follow-up. The median survival was 3.4 weeks (95% confidence interval 2.6-4.3). Factors associated with higher mortality were age, serum calcium at admission, previous history of neoplasia, etiology other than multiple myeloma, and noncorrection of hypercalcemia.

CONCLUSIONS

In hospitalized patients, paraneoplastic hypercalcemia was associated with high short-term mortality. Several factors associated with a worse prognosis were identified in these patients.

Characteristics of hospitalized patients with hypercalcemia in the province of Malaga: a longitudinal, retrospective, multicenter study

BACKGROUND AND OBJECTIVE

There are limited studies analyzing hypercalcemia in hospitalized patients. Our objectives were to describe the clinical characteristics of hospitalized patients with hypercalcemia, estimate its prevalence in the hospital setting, analyze the rate of correction of hypercalcemia, and identify prognostic variables.

MATERIALS AND METHODS

Observational, longitudinal, retrospective, and bicentric study. Adult patients admitted to two hospitals in Málaga (2014-2018) with a diagnosis of hypercalcemia were included. The minimum follow-up was 2 years or until death.

RESULTS

A total of 205 patients with hypercalcemia were included (incidence: 0.13%). The mean age (SD) was 68.2 (13.1) years, with a predominance of males (55.1%). The median (IQR) serum calcium at admission was 13.1 (11.8-14.6) mg/dl. The most common etiologies were neoplasms (75.1%), primary hyperparathyroidism, and medications (both 8.8%). The median (IQR) follow-up period was 5.1 (1.7-60.3) weeks. The most commonly used treatments were fluid therapy (86.8%), loop diuretics (70.9%), bisphosphonates (60.7%), and glucocorticoids (46.2%). The rate of correction of hypercalcemia was 65.2%, with a median (IQR) of 6 (3-10) days. The mortality rate was 81.5%. The median (95% CI) survival was 5.1 (3-7.3) weeks. Factors associated with higher mortality were advanced age, neoplastic etiology, serum calcium at admission, and failure to correct hypercalcemia.

CONCLUSIONS

Hypercalcemia in hospitalized patients is mainly due to neoplastic processes and is associated with high mortality. We observed a low rate of adherence to recommendations for the management of hypercalcemia.

Electrolytes and Nutritional Element Assessment among Iraqi Cancer Patients Receiving Chemotherapy

INTRODUCTION: Cancer may lead to abnormalities in electrolyte levels and acid-base disturbances in affected patients that could be induced by the tumor itself or by chemotherapy treatment. Thus, early detection is vital to improve short-term outcome and quality of life. AIM: This study aims to assess the electrolyte and protein changes in cancer patients on chemotherapy. MATERIALS AND METHODS: A cohort study was carried out on 100 newly diagnosed patients with cancer in Al-Amal National Radiation Oncology Hospital in Baghdad, Iraq, during the period from January 2019 to July 2019. An assessment of the studied samples was conducted as a baseline measure before receiving chemotherapy and after the third cycle of that treatment. Quantitative parameters included measurements of serum magnesium, calcium, sodium, chloride, potassium, zinc, Hb1Ac, total protein, and ferritin. Data analysis was carried out using Student’s t-test for variable levels. Level of significance of ≤0.05 was considered as significant. RESULTS: The studied sample comprised 77 females (77%) and 23 males (23%). There were significant decreases in the levels of magnesium and zinc while no significant changes were noted in the levels of other electrolytes. On the other hand, there was a significant decrease in the level of proteins and a significant rise in HBA1c and ferritin. CONCLUSION: Cancer patients on chemotherapy regimens suffer from major changes in the levels of vitamins, elements, and neurotransmitter that affect their lifestyle, survival, and prognosis. Frequent regular monitoring of such changes is required to harvest a positive impact on the lifestyle of cancer patients lifestyle and their outcome.

Can conventional clinical chemistry tests help doctors in the monitoring of oncology patients?

The use of laboratory assays in the diagnostic care of oncology patients can markedly increase the efficacy of cancer treatments. Many cancer-specific biomarker assays have been developed. However, the use of these has some limitations due to their cost. Moreover, not every diagnostic laboratory can perform a complete set of these assays. On the other hand, the smart use of conventional clinical chemistry tests could improve the management of cancer. They could be especially valuable tools in the long-term care of patients with a verified diagnosis. In this review, we discuss the utilization of the conventional clinical chemistry assays for the diagnosis, monitoring and prognosis of various oncological diseases. The use of conventional blood tests to assess the levels of chemical elements, metabolites and proteins (including enzymatic activity measurements) in the care of oncology patients is discussed. We have shown that some clinical chemistry assays could be used in the management of distinct kinds of cancer.

Systematic overestimation of human serum albumin by capillary zone electrophoresis method due to monoclonal immunoglobulin interferences

BACKGROUND

The capillary zone electrophoresis method of albumin measurement is frequently used in monoclonal gammopathy patients but some studies suggest poor performances of the method in this population. The aim of this study was to analyse the impact of serum monoclonal immunoglobulins on human serum albumin determination by capillary zone electrophoresis method compared to other available methods.

METHOD

We prospectively measured albumin in 100 freshly collected non-frozen serum samples in a monoclonal gammopathy patients population, by using four different methods: the capillary zone electrophoresis method, the bromocresol purple dye method, the nephelometric method and the turbidimetric method. Differences in albumin values between the different methods were analysed with respect to serum monoclonal immunoglobulin concentration. These differences were further investigated by measuring albumin levels in human serum samples spiked with exogenous monoclonal immunoglobulins.

RESULTS

Human serum albumin difference values between capillary zone electrophoresis compared to immunonephelometry method are significantly correlated with increasing monoclonal immunoglobulins concentrations: regression analyses revealed a correlation coefficient r² = 0.60 and a slope of 0.14 (0.12-0.17, 95% confidence interval). The capillary zone electrophoresis method overestimated serum albumin levels by up to 67% (12 g/L) when monoclonal immunoglobulin level was 63 g/L. The determination of albumin levels in human serum samples spiked with exogenous monoclonal immunoglobulins showed an overestimation of human serum albumin measurement by the capillary zone electrophoresis method proportional to the amount of monoclonal immunoglobulin added in the serum with a slope of 0.19 (0.18-0.20, 95% confidence interval).

CONCLUSION

Monoclonal immunoglobulins directly interfere with serum albumin measurement by the capillary zone electrophoresis method leading to a systematic overestimation of serum albumin concentrations proportional to the serum monoclonal immunoglobulin level.

Predictive accuracy of serum total calcium for both critically high and critically low ionized calcium in critical illness

BACKGROUND

The accuracy of total calcium and its corrected value for predicting critically high and critically low ionized calcium in critical illness is controversial. The aim of this study was to investigate whether the concentration of total serum calcium, either corrected for albumin or not, could predict critically high or low values in critical illness.

METHODS

This report describes a retrospective study using the Medical Information Mart for Intensive Care (MIMIC) III database. Test panels that contained serum albumin, total calcium, and ionized calcium (named ATI panels) with order time intervals of less than one hour were extracted. The predictive accuracy of total calcium, either corrected for albumin or not, was assessed using receiver operating characteristic (ROC) curve analysis.

RESULTS

A total of 12 118 ATIs with 103 critically low and 92 critically high ionized calcium results were extracted. The areas under ROC curves (AUCs) of corrected and uncorrected total calcium for predicting critically low ionized calcium were 0.69 (95% CI: 0.61-0.76) and 0.70 (95% CI: 0.63-0.78), respectively. For predicting critically high ionized calcium, the AUCs were 0.98 (95% CI: 0.97-1.00) and 0.97 (95% CI: 0.95-1.00), respectively. With positive predictive values (PPVs) of 0.05 and 0.10, the sensitivities (both corrected and uncorrected) were approximately 0.50 for predicting critically low ionized calcium and 0.95 for predicting critically high ionized calcium.

CONCLUSIONS

Total calcium, either corrected for albumin or not, is not a reliable test to predict critically low ionized calcium in critical illness. Total calcium's predictive accuracy for critically high ionized calcium is high.