Evaluation of the Accuracy of Capillary Hydroxybutyrate Measurement Compared with Other Measurements in the Diagnosis of Diabetic Ketoacidosis: A Systematic Review

Abstract

A complication of diabetes is diabetic ketoacidosis (DKA), which if left untreated is a life threatening condition. Prompt and accurate diagnosis of DKA is required for the commencement of life saving interventions. Measurements of ketone bodies in DKA have usually been through nitroprusside urine acetoacetate testing. The aim of this systematic review was to examine whether capillary β-hydroxybutyrate (β-OHB) testing is more accurate compared to other diagnostic methods of DKA. The following electronic databases were searched: EBSCO Host, MEDLINE, PSYCHInfo, CINAHL and Science Direct for publications from 1 January 2005 and up to and including 1 January 2016. Inclusion criteria were: Adults 18 years and over and known type 1 or type 2 diabetes. Retrospective and prospective observation studies were included. A total of nine studies met the inclusion criteria. Capillary β-OHB was found to have high sensitivity, specificity, positive predictive value and negative predictive value in identifying DKA compared to urinary ketone testing.

International Consensus on Risk Management of Diabetic Ketoacidosis in Patients With Type 1 Diabetes Treated With Sodium–Glucose Cotransporter (SGLT) Inhibitors

“…We recommend patient selfmeasurement of capillary blood ketones, specifically b-hydroxybutyrate (the most prevalent ketone body) as a matter of routine in assessing the metabolic state of patients with type 1 diabetes treated with SGLT inhibitors (36)(37)(38)(39)(40). In patients who cannot afford or do not have access to capillary blood ketone measurements, urine ketone measurements are acceptable.…”

Urine dipsticks are not accurate for detecting mild ketosis during a severely energy restricted diet

“…Our findings extend those of previous studies, which have compared the accuracy of urine dipsticks with blood ketone monitors to diagnose ketoacidosis in people with diabetes. 20 A recent systematic review of this topic identified five studies-three of which showed urine dipsticks to have high sensitivity (≥89%, range 89% to 98%) and variable specificity (35% to 100%). 20 In one of the other two of five studies, sensitivity of the urine dipsticks was low (33%), but specificity was high (94%), and in the remaining study, sensitivity and specificity were not reported.…”

“…Compared to blood monitors, urine dipsticks are equally able to identify 'true positive' cases of ketoacidosis in people with diabetes (high sensitivity), albeit they have a lower ability to identify 'true negatives' among people with diabetic ketoacidosis (lower specificity). [17][18][19][20] As well as being less invasive than blood ketone monitors (some people may be averse to pricking their finger), urine dipsticks are at least seven times cheaper than blood monitors, at around US$0.10 per dipstick compared with around US $0.70 per test trip for the blood monitors. Furthermore, the blood ketone monitor itself typically costs at least another US$25.00.…”

Urine versus blood ketones

“…Similarly, hydration status can affect results with dehydration leading to false positive results and excessive fluid intake leading to false negative results. A urine sample is required and this may delay the diagnosis if this is difficult to obtain. Measurements do not accurately reflect current conditions if the urine has been in the bladder for several hours. Drugs can affect results; medications containing a sulphydryl group, for example captopril, and levodopa can cause false positives. Vitamin C may lead to a false negative result Test strips exposed to air degrade over time and both manufacturers of the strips quote an expiry of six months after opening. Urine ketone strips are visually read.…”