Precision and accuracy: Comparison of point-of-care and laboratory glucose concentrations in cardiothoracic surgery patients

Quin Denfeld, Teresa T. Goodell, Kelly N. Stafford, Steven (Steve) Kazmierczak

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

BACKGROUND:: There have been variable results on the practice of tight glycemic control, and studies have demonstrated that point-of-care (POC) glucometers have variable accuracy. OBJECTIVE:: The purpose of this study was to determine the difference between blood glucose concentrations obtained from POC glucometers as compared with laboratory results in cardiothoracic surgery (CTS) patients. METHODS:: This was a descriptive study on a convenience sample of 46 CTS patients. A single sample of arterial blood was collected and analyzed at the bedside with the POC glucometer and in the laboratory to obtain a serum glucose concentration and hematocrit (Hct). A paired t test was used to compare the mean differences along with Spearman ρ correlation to examine the relationship between difference scores and Hct. RESULTS:: The POC glucose was significantly higher than the laboratory result (t = 8.5, P <.001) with a mean of 12.3 (SD, 9.8) mg/dL. Spearman ρ correlation between the difference scores and Hct was -0.43, P = .003. Using a tercile split, groups with Hct of less than 26% (n = 16) and greater than 29% (n = 15) were identified. The unpaired t test on the mean difference scores of these 2 groups was t = -2.7, P <.01, with an overall mean difference 8.6 mg/dL (95% confidence interval, -15 to -2.2). The mean difference was 16.3 in the low-Hct group and 7.8 in the high-Hct group. CONCLUSIONS:: Point-of-care glucometer results differ significantly from laboratory glucose concentrations, with the difference widening as the Hct decreases. This raises the concern about using POC devices to provide tight glycemic control in CTS patients.

Original languageEnglish (US)
Pages (from-to)512-518
Number of pages7
JournalJournal of Cardiovascular Nursing
Volume26
Issue number6
DOIs
StatePublished - Nov 2011

Fingerprint

Point-of-Care Systems
Hematocrit
Glucose
Blood Glucose
Confidence Intervals
Equipment and Supplies

Keywords

  • blood glucose
  • hypoglycemia
  • intensive care units
  • point-of-care systems
  • thoracic surgery

ASJC Scopus subject areas

  • Advanced and Specialized Nursing
  • Cardiology and Cardiovascular Medicine
  • Medicine(all)

Cite this

Precision and accuracy : Comparison of point-of-care and laboratory glucose concentrations in cardiothoracic surgery patients. / Denfeld, Quin; Goodell, Teresa T.; Stafford, Kelly N.; Kazmierczak, Steven (Steve).

In: Journal of Cardiovascular Nursing, Vol. 26, No. 6, 11.2011, p. 512-518.

Research output: Contribution to journalArticle

@article{c0aa54e0375b4514ac372e59f9ae238a,
title = "Precision and accuracy: Comparison of point-of-care and laboratory glucose concentrations in cardiothoracic surgery patients",
abstract = "BACKGROUND:: There have been variable results on the practice of tight glycemic control, and studies have demonstrated that point-of-care (POC) glucometers have variable accuracy. OBJECTIVE:: The purpose of this study was to determine the difference between blood glucose concentrations obtained from POC glucometers as compared with laboratory results in cardiothoracic surgery (CTS) patients. METHODS:: This was a descriptive study on a convenience sample of 46 CTS patients. A single sample of arterial blood was collected and analyzed at the bedside with the POC glucometer and in the laboratory to obtain a serum glucose concentration and hematocrit (Hct). A paired t test was used to compare the mean differences along with Spearman ρ correlation to examine the relationship between difference scores and Hct. RESULTS:: The POC glucose was significantly higher than the laboratory result (t = 8.5, P <.001) with a mean of 12.3 (SD, 9.8) mg/dL. Spearman ρ correlation between the difference scores and Hct was -0.43, P = .003. Using a tercile split, groups with Hct of less than 26{\%} (n = 16) and greater than 29{\%} (n = 15) were identified. The unpaired t test on the mean difference scores of these 2 groups was t = -2.7, P <.01, with an overall mean difference 8.6 mg/dL (95{\%} confidence interval, -15 to -2.2). The mean difference was 16.3 in the low-Hct group and 7.8 in the high-Hct group. CONCLUSIONS:: Point-of-care glucometer results differ significantly from laboratory glucose concentrations, with the difference widening as the Hct decreases. This raises the concern about using POC devices to provide tight glycemic control in CTS patients.",
keywords = "blood glucose, hypoglycemia, intensive care units, point-of-care systems, thoracic surgery",
author = "Quin Denfeld and Goodell, {Teresa T.} and Stafford, {Kelly N.} and Kazmierczak, {Steven (Steve)}",
year = "2011",
month = "11",
doi = "10.1097/JCN.0b013e31820a7bf4",
language = "English (US)",
volume = "26",
pages = "512--518",
journal = "Journal of Cardiovascular Nursing",
issn = "0889-4655",
publisher = "Lippincott Williams and Wilkins",
number = "6",

}

TY - JOUR

T1 - Precision and accuracy

T2 - Comparison of point-of-care and laboratory glucose concentrations in cardiothoracic surgery patients

AU - Denfeld, Quin

AU - Goodell, Teresa T.

AU - Stafford, Kelly N.

AU - Kazmierczak, Steven (Steve)

PY - 2011/11

Y1 - 2011/11

N2 - BACKGROUND:: There have been variable results on the practice of tight glycemic control, and studies have demonstrated that point-of-care (POC) glucometers have variable accuracy. OBJECTIVE:: The purpose of this study was to determine the difference between blood glucose concentrations obtained from POC glucometers as compared with laboratory results in cardiothoracic surgery (CTS) patients. METHODS:: This was a descriptive study on a convenience sample of 46 CTS patients. A single sample of arterial blood was collected and analyzed at the bedside with the POC glucometer and in the laboratory to obtain a serum glucose concentration and hematocrit (Hct). A paired t test was used to compare the mean differences along with Spearman ρ correlation to examine the relationship between difference scores and Hct. RESULTS:: The POC glucose was significantly higher than the laboratory result (t = 8.5, P <.001) with a mean of 12.3 (SD, 9.8) mg/dL. Spearman ρ correlation between the difference scores and Hct was -0.43, P = .003. Using a tercile split, groups with Hct of less than 26% (n = 16) and greater than 29% (n = 15) were identified. The unpaired t test on the mean difference scores of these 2 groups was t = -2.7, P <.01, with an overall mean difference 8.6 mg/dL (95% confidence interval, -15 to -2.2). The mean difference was 16.3 in the low-Hct group and 7.8 in the high-Hct group. CONCLUSIONS:: Point-of-care glucometer results differ significantly from laboratory glucose concentrations, with the difference widening as the Hct decreases. This raises the concern about using POC devices to provide tight glycemic control in CTS patients.

AB - BACKGROUND:: There have been variable results on the practice of tight glycemic control, and studies have demonstrated that point-of-care (POC) glucometers have variable accuracy. OBJECTIVE:: The purpose of this study was to determine the difference between blood glucose concentrations obtained from POC glucometers as compared with laboratory results in cardiothoracic surgery (CTS) patients. METHODS:: This was a descriptive study on a convenience sample of 46 CTS patients. A single sample of arterial blood was collected and analyzed at the bedside with the POC glucometer and in the laboratory to obtain a serum glucose concentration and hematocrit (Hct). A paired t test was used to compare the mean differences along with Spearman ρ correlation to examine the relationship between difference scores and Hct. RESULTS:: The POC glucose was significantly higher than the laboratory result (t = 8.5, P <.001) with a mean of 12.3 (SD, 9.8) mg/dL. Spearman ρ correlation between the difference scores and Hct was -0.43, P = .003. Using a tercile split, groups with Hct of less than 26% (n = 16) and greater than 29% (n = 15) were identified. The unpaired t test on the mean difference scores of these 2 groups was t = -2.7, P <.01, with an overall mean difference 8.6 mg/dL (95% confidence interval, -15 to -2.2). The mean difference was 16.3 in the low-Hct group and 7.8 in the high-Hct group. CONCLUSIONS:: Point-of-care glucometer results differ significantly from laboratory glucose concentrations, with the difference widening as the Hct decreases. This raises the concern about using POC devices to provide tight glycemic control in CTS patients.

KW - blood glucose

KW - hypoglycemia

KW - intensive care units

KW - point-of-care systems

KW - thoracic surgery

UR - http://www.scopus.com/inward/record.url?scp=80054890338&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80054890338&partnerID=8YFLogxK

U2 - 10.1097/JCN.0b013e31820a7bf4

DO - 10.1097/JCN.0b013e31820a7bf4

M3 - Article

C2 - 21263334

AN - SCOPUS:80054890338

VL - 26

SP - 512

EP - 518

JO - Journal of Cardiovascular Nursing

JF - Journal of Cardiovascular Nursing

SN - 0889-4655

IS - 6

ER -