What are the diagnostic criteria for Diabetic Ketoacidosis (DKA)?

From the Guidelines

Diagnosing diabetic ketoacidosis (DKA) requires a combination of clinical assessment and laboratory testing, with the most recent and highest quality study suggesting that DKA diagnostic criteria include blood glucose >250 mg/dl, venous pH <7.3, bicarbonate <15 mEq/l, and moderate ketonuria or ketonemia 1. To diagnose DKA, look for the classic triad of hyperglycemia, metabolic acidosis, and ketosis. Patients often present with symptoms including excessive thirst, frequent urination, nausea, vomiting, abdominal pain, weakness, fatigue, confusion, and a fruity breath odor. Initial evaluation should include:

• A comprehensive metabolic panel to assess glucose levels, electrolytes (particularly potassium, as it may be depleted), and kidney function
• An arterial blood gas analysis is essential to determine the severity of acidosis, with an anion gap calculation (typically >12 mEq/L in DKA)
• Point-of-care testing for beta-hydroxybutyrate provides a more accurate measure of ketosis than urine ketones Additional tests should include:
• A complete blood count
• Urinalysis
• Appropriate cultures if infection is suspected as a trigger Clinicians should also consider:
• An electrocardiogram to assess for cardiac complications
• Chest X-ray if respiratory symptoms are present DKA occurs when insulin deficiency leads to increased counter-regulatory hormones, resulting in excessive glucose production, decreased glucose utilization, and increased lipolysis with subsequent ketone formation, causing the characteristic metabolic derangements. The most important laboratory tests for diagnosing DKA are:
• Blood glucose levels
• Venous pH
• Bicarbonate levels
• Ketone levels (either urine or blood) It is essential to note that the measurement of beta-hydroxybutyrate in the blood is the preferred method for monitoring DKA, as it provides a more accurate measure of ketosis than urine ketones 1.

From the Research

Diagnostic Criteria for Diabetic Ketoacidosis

To diagnose diabetic ketoacidosis (DKA), the following criteria must be present:

• Elevated blood glucose levels or a family history of diabetes mellitus (D) 2
• The presence of high urinary or blood ketoacids (K) 2
• A high anion gap metabolic acidosis (A) 2

Clinical Presentation and Laboratory Findings

Common symptoms of DKA include:

• Polyuria with polydipsia (98%) 3
• Weight loss (81%) 3
• Fatigue (62%) 3
• Dyspnea (57%) 3
• Vomiting (46%) 3
• Preceding febrile illness (40%) 3
• Abdominal pain (32%) 3
• Polyphagia (23%) 3 Laboratory findings may include:
• Serum glucose level greater than 250 mg per dL 3
• pH less than 7.3 3
• Serum bicarbonate level less than 18 mEq per L 3
• Elevated serum ketone level 3
• Dehydration 3

Diagnostic Tests

The following tests can be used to diagnose DKA:

• Measurement of A1C, blood urea nitrogen, creatinine, serum glucose, electrolytes, pH, and serum ketones 3
• Complete blood count 3
• Urinalysis 3
• Electrocardiography 3
• Calculation of anion gap and osmolar gap 3
• Urine ketone dip test (UKDT) as a screen for ketonemia in DKA and ketosis 4

Ketone Measurement and Interpretation

Ketone measurement is an important aspect of DKA diagnosis and management:

• Blood ketones can be measured using hand-held, point-of-care ketone meters 5
• Urine ketones can be measured using the UKDT 4
• The sensitivity of the UKDT for the detection of ketonemia in patients with DKA or DK is 97% (95% CI, 94% to 99%) 4