The Threshold of Serum Anion Gap as a Screening Tool for Organic Acidosis

NCT04975906 | Completed

• 1 other identifier: SingHealth CIRB: 2019/2463
• Study Type: observational
• Target: 16,475
• Locations: 1 country
• Sites: 1

Brief Summary

Background: The serum anion gap (AG) is commonly used as a screening tool for acid-base disorders. With modern laboratory techniques using ion-selective electrodes to measure the main electrolyte components of the AG, our definition high AG (HAGMA) should be reviewed. Aim: This study aims to assess the diagnostic value of AG and to determine a diagnostic threshold for HAGMA in a high-prevalence clinical setting. Method: Computerized extraction of anonymised data from electronic medical records was performed. A pre-defined criteria included all inpatients of an acute-care hospital who had measurements for organic acids (lactate, ketone or salicylate) paired with a serum urea, electrolyte and creatinine panel.

Conditions

Metabolic Acidosis; Critical Illness; Anion Gap Acidosis; Lactic Acidosis; Keto Acidosis; Acid Base Disorder

Keywords

Anion Gap; Metabolic Acidosis; Lactic Acidosis; Ketoacidosis; Screening Test

Outcome Measures

Primary Outcomes (2)

• Area Under the Curve of Receiver Operating Characteristics

  An area under the curve (AUC) of receiver operating characteristics (ROC) of Anion Gap for the presence of organic acidosis will be calculated. An AUC \>0.8 suggests that Anion Gap performs well as a test for the presence of organic acidosis.

  End of study period, estimated 3 years

• An optimal cut-off threshold of Anion Gap

  The optimal cut-off threshold will be determined. At each cut-off level. the sensitivity and specificity will be calculated. One recommended cut-off value for Anion Gap with a sensitivity \>95% will be accepted.

  End of study period, estimated 3 years

Secondary Outcomes (1)

• Subgroup Analysis for Performance of Anion Gap as a screening test for Organic Acidosis

  End of study period, estimated 3 years

Study Arms (1)

Participants

All inpatient admissions with serum lactate, ketones and/or salicylates performed, and with urea, electrolytes and creatinine at the same time. The patients will be grouped into patients with organic (gap) acidosis (elevated serum lactate, ketones and/or salicylates) and patients with no organic acidosis.

Eligibility Criteria

• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Inpatients in acute care hospital admitted from 01 July 2017 to 31 December 2019 who were being assessed for organic acidosis

You may qualify if:

• Admitted from 01 July 2017 to 31 December 2019
• Patients who have had blood lactate, blood ketones and serum salicylates performed during this time period
• Patient who also had urea / creatinine and a comprehensive panel of electrolytes performed up to +/-12h of blood lactate, blood ketones and serum salicylates being performed

You may not qualify if:

• Patient who did not have blood lactate, blood ketones and serum salicylates performed during this time period
• Patient who did not have urea / creatinine and a comprehensive panel of electrolytes performed up to +/-12h of blood lactate, blood ketones and serum salicylates being performed

Sponsors & Collaborators

• Changi General Hospital: lead

Study Sites (1)

Changi General Hospital

Singapore, 529889, Singapore

Location

Related Publications (4)

• Winter SD, Pearson JR, Gabow PA, Schultz AL, Lepoff RB. The fall of the serum anion gap. Arch Intern Med. 1990 Feb;150(2):311-3.

  PMID: 2302006 BACKGROUND

• Sadjadi SA, Manalo R, Jaipaul N, McMillan J. Ion-selective electrode and anion gap range: What should the anion gap be? Int J Nephrol Renovasc Dis. 2013 Jun 7;6:101-5. doi: 10.2147/IJNRD.S44689. Print 2013.

  PMID: 23776389 BACKGROUND

• Lolekha PH, Vanavanan S, Lolekha S. Update on value of the anion gap in clinical diagnosis and laboratory evaluation. Clin Chim Acta. 2001 May;307(1-2):33-6. doi: 10.1016/s0009-8981(01)00459-4.

  PMID: 11369334 BACKGROUND

• Ayala-Lopez N, Harb R. Interpreting Anion Gap Values in Adult and Pediatric Patients: Examining the Reference Interval. J Appl Lab Med. 2020 Jan 1;5(1):126-135. doi: 10.1373/jalm.2019.029496.

  PMID: 32445342 BACKGROUND

MeSH Terms

Conditions

Acidosis; Critical Illness; Acidosis, Lactic; Ketosis

Condition Hierarchy (Ancestors)

Acid-Base Imbalance; Metabolic Diseases; Nutritional and Metabolic Diseases; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Chang Y Chionh

  Changi General Hospital

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Senior Consultant

Study Record Dates

• First Submitted: May 28, 2021
• First Posted: July 26, 2021
• Study Start: July 1, 2017
• Primary Completion: December 31, 2021
• Study Completion: June 6, 2023
• Last Updated: June 15, 2023

Record last verified: 2023-06

Data Sharing

• IPD Sharing: Will not share

Locations

SG (1)