Prospective study comparing the outcome of a population-specific adjusted calcium equation to ionized calcium

N. Jassam; K. Hayden; R. Dearman; V. Allgar; J. H. Barth

doi:10.1177/0004563220926542

Prospective study comparing the outcome of a population-specific adjusted calcium equation to ionized calcium

N. Jassam^*, K. Hayden, R. Dearman, V. Allgar, J. H. Barth

^*Corresponding author for this work

Peninsula Medical School

Research output: Contribution to journal › Article › peer-review

Abstract

Background Calcium circulates bound to albumin and changes in albumin concentration will therefore affect total calcium measurements. In order to mitigate this, correction factors are frequently used. The most widely used correction equation was described by Payne and colleagues in 1973. This equation was derived from well-defined hospitalized patients’ data. Current clinical practice is consistent with the general application of the adjusted calcium equation irrespective of clinical setting. This study aims to assess the validity of this approach by the derivation of a community care-specific adjusted calcium equation (‘community equation’) and the comparison of its performance to a hospitalized patient equation and ionized calcium. Method Retrospective data were collected according to Payne’s criteria from an inpatient and community care setting. Data were used to derive the two equations: the in-patient equation and community equation. The outcome of these equations was compared with ionized calcium obtained from 123 healthy participants. Results The community equation correctly identified the calcium status of 92% of the 123 healthy participants, while the inpatient equation identified 46% only. Regression analysis against ionized calcium showed a higher R2 for the community equation than for the inpatient equation. Furthermore, we have shown that mean albumin and calcium concentrations are significantly different between these two populations. Conclusion In this study, we found that the diagnostic accuracy of the adjusted calcium equation in ambulant patients was improved by the derivation of a population-specific equation for the community care setting.

Original language	English
Pages (from-to)	316-324
Number of pages	0
Journal	Annals of Clinical Biochemistry: International Journal of Laboratory Medicine
Volume	57
Issue number	4
Early online date	4 Jun 2020
DOIs	https://doi.org/10.1177/0004563220926542
Publication status	Published - Jul 2020

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title = "Prospective study comparing the outcome of a population-specific adjusted calcium equation to ionized calcium",

abstract = "Background Calcium circulates bound to albumin and changes in albumin concentration will therefore affect total calcium measurements. In order to mitigate this, correction factors are frequently used. The most widely used correction equation was described by Payne and colleagues in 1973. This equation was derived from well-defined hospitalized patients{\textquoteright} data. Current clinical practice is consistent with the general application of the adjusted calcium equation irrespective of clinical setting. This study aims to assess the validity of this approach by the derivation of a community care-specific adjusted calcium equation ({\textquoteleft}community equation{\textquoteright}) and the comparison of its performance to a hospitalized patient equation and ionized calcium. Method Retrospective data were collected according to Payne{\textquoteright}s criteria from an inpatient and community care setting. Data were used to derive the two equations: the in-patient equation and community equation. The outcome of these equations was compared with ionized calcium obtained from 123 healthy participants. Results The community equation correctly identified the calcium status of 92% of the 123 healthy participants, while the inpatient equation identified 46% only. Regression analysis against ionized calcium showed a higher R2 for the community equation than for the inpatient equation. Furthermore, we have shown that mean albumin and calcium concentrations are significantly different between these two populations. Conclusion In this study, we found that the diagnostic accuracy of the adjusted calcium equation in ambulant patients was improved by the derivation of a population-specific equation for the community care setting. ",

author = "N. Jassam and K. Hayden and R. Dearman and V. Allgar and Barth, {J. H.}",

year = "2020",

month = jul,

doi = "10.1177/0004563220926542",

language = "English",

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pages = "316--324",

journal = "Annals of Clinical Biochemistry: International Journal of Laboratory Medicine",

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T1 - Prospective study comparing the outcome of a population-specific adjusted calcium equation to ionized calcium

AU - Jassam, N.

AU - Hayden, K.

AU - Dearman, R.

AU - Allgar, V.

AU - Barth, J. H.

PY - 2020/7

Y1 - 2020/7

N2 - Background Calcium circulates bound to albumin and changes in albumin concentration will therefore affect total calcium measurements. In order to mitigate this, correction factors are frequently used. The most widely used correction equation was described by Payne and colleagues in 1973. This equation was derived from well-defined hospitalized patients’ data. Current clinical practice is consistent with the general application of the adjusted calcium equation irrespective of clinical setting. This study aims to assess the validity of this approach by the derivation of a community care-specific adjusted calcium equation (‘community equation’) and the comparison of its performance to a hospitalized patient equation and ionized calcium. Method Retrospective data were collected according to Payne’s criteria from an inpatient and community care setting. Data were used to derive the two equations: the in-patient equation and community equation. The outcome of these equations was compared with ionized calcium obtained from 123 healthy participants. Results The community equation correctly identified the calcium status of 92% of the 123 healthy participants, while the inpatient equation identified 46% only. Regression analysis against ionized calcium showed a higher R2 for the community equation than for the inpatient equation. Furthermore, we have shown that mean albumin and calcium concentrations are significantly different between these two populations. Conclusion In this study, we found that the diagnostic accuracy of the adjusted calcium equation in ambulant patients was improved by the derivation of a population-specific equation for the community care setting.

AB - Background Calcium circulates bound to albumin and changes in albumin concentration will therefore affect total calcium measurements. In order to mitigate this, correction factors are frequently used. The most widely used correction equation was described by Payne and colleagues in 1973. This equation was derived from well-defined hospitalized patients’ data. Current clinical practice is consistent with the general application of the adjusted calcium equation irrespective of clinical setting. This study aims to assess the validity of this approach by the derivation of a community care-specific adjusted calcium equation (‘community equation’) and the comparison of its performance to a hospitalized patient equation and ionized calcium. Method Retrospective data were collected according to Payne’s criteria from an inpatient and community care setting. Data were used to derive the two equations: the in-patient equation and community equation. The outcome of these equations was compared with ionized calcium obtained from 123 healthy participants. Results The community equation correctly identified the calcium status of 92% of the 123 healthy participants, while the inpatient equation identified 46% only. Regression analysis against ionized calcium showed a higher R2 for the community equation than for the inpatient equation. Furthermore, we have shown that mean albumin and calcium concentrations are significantly different between these two populations. Conclusion In this study, we found that the diagnostic accuracy of the adjusted calcium equation in ambulant patients was improved by the derivation of a population-specific equation for the community care setting.

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DO - 10.1177/0004563220926542

M3 - Article

SN - 0004-5632

VL - 57

SP - 316

EP - 324

JO - Annals of Clinical Biochemistry: International Journal of Laboratory Medicine

JF - Annals of Clinical Biochemistry: International Journal of Laboratory Medicine

IS - 4

ER -

Prospective study comparing the outcome of a population-specific adjusted calcium equation to ionized calcium

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