Post-mortem urine dipstick analysis for hyperglycemia and ketoacidosis: observer agreement and diagnostic value

International Journal of Legal Medicine https://doi.org/10.1007/s00414-025-03477-3 ORIGINAL ARTICLE Post-mortem urine dipstick analysis for hyperglycemia and ketoacidosis: observer agreement and diagnostic value Joanna M. Glengarry1,2 · Ben Thompson1 · Maria Pricone1 · Melanie S. Archer1,2 · Hans H. de Boer1,2 Received: 6 December 2024 / Accepted: 18 March 2025 © Crown 2025 Abstract The post-mortem diagnosis of hyperglycemia and/or ketoacidosis is challenging and usually requires costly ancillary testing of vitreous humor or serum samples. A screening tool that would help to determine whether ancillary testing is needed is therefore desirable. The aim of this study was to add to the literature testing the validity and diagnostic utility of postmortem dipstick urinalysis. More specifically, we determined inter-observer agreement of visual dipstick assessment, the correlation between glucose and ketone urine dipstick scores and formal laboratory testing results, and the diagnostic value of specific dipstick scores expressed with likelihood ratios. Results demonstrate almost perfect interobserver agreement for 108 glucose dipstick scores (Fleiss’ kappa 0.914) but only moderate interobserver agreement for 96 ketones dipstick scores (Fleiss’ kappa 0.467). Dipstick glucose scores correlated strongly with vitreous humor glucose levels (Spearman’s rank correlation coefficient of 0.841, n = 107). Correlation between ketone dipstick scores and serum levels of beta-hydroxybutyrate (BHB) and blood acetone was also positive but much weaker (0.317, n = 91; and 0.411, n = 92, respectively). The diagnostic value of specific dipstick scores was determined by calculating likelihood ratios for substantial hyperglycemia (vitreous humor glucose > 10 mmol/L), substantial ketoacidosis (serum BHB > 2.50 mmol/L) and elevated blood acetone (> 20 mg/L). Our results suggest substantial screening potential of dipstick urinalysis for glucose, especially when scores are at the lower and higher end of the spectrum. Overall, dipstick analysis results for ketones must be interpreted with great caution. A sub analysis of the data showed that a serum BHB above 2.50 mmol/L was only seen in 1.8% of cases without demonstrable acetone (> 20 mg/L). Keywords Acetone · Autopsy · Biochemistry · Dipstick · Forensic medicine · Forensic pathology · Glucose · Hyperglycemia · Ketones · BHB · Point of care testing · Post-mortem · Urinalysis · Urine Introduction The human body requires internal physiological and metabolic stability (or ‘homeostasis’) to survive and function. If homeostasis cannot be maintained, bodily functions can deteriorate rapidly, which may progress into unexpected and/or unexplained death. As such, forensic pathologists are regularly confronted with cases where metabolic and Hans H. de Boer 1 Victorian Institute of Forensic Medicine, 65 Kavanagh St, Southbank, VIC 3006, Australia 2 Department of Forensic Medicine, Monash University, Southbank, VIC 3006, Australia physiological derangements may play an important part in the cause or mechanism of death. Unfortunately, such derangements are not easy to diagnose in a post-mortem setting [1]. One requires a degree of clinical suspicion to contemplate their presence and their diagnosis relies heavily on ancillary biochemical testing, as they do not necessarily present with abnormalities that are evident on external, internal, histological or radiological examination. The interpretation of post-mortem biochemical analyses furthermore requires knowledge of post-mortem artefacts, whilst considering additional information, such as the deceased’s medical history, the circumstances of death and the decomposition stage. The usual starting point for post-mortem biochemical analysis is the analysis of vitreous humor (VH) [2], which should be requested in most cases in which no 13 International Journal of Legal Medicine cause of death can be given after autopsy. In selected cases, this analysis may be complemented with testing for ketones (beta-hydroxybutyrate (BHB) and acetone), for instance in vitreous humor, whole blood or serum. These analyses can however be regarded as relatively costly and labor intensive, especially due to the potential need to send samples to specialized biochemical laboratories. Not all mortuaries have access to such facilities, and for those who do, the ancillary testing is usually an additional burden on their budget. The number of cases in which the biochemical analysis proves to be negative for substantial abnormalities is anecdotally high. A screening tool that helps to determine whether biochemical analysis should be performed is therefore desirable. In a clinical setting, urine dipstick analysis is used as point of care test (POCT) for disorders such as ketosis, diabetes, or urinary tract infections [3]. These dipsticks use absorbent, reactive pads and semi-quantitative color coding to indicate pH, or the concentration of various substances such as glucose, nitrate, bilirubin, ketones, and lymphocytes. They are cheap, easy to use, and provide a result within seconds [4]. The World Health Organization formulated the “ASSURED” criteria for POCTs, indicating that they should be Affordable, Sensitive, Specific, Userfriendly, Rapid and Robust, Equipment-free and Deliverable to end users [5]. In theory, urine dipsticks have much potential to also meet these criteria in the post-mortem setting [6]. In a review on the topic of all types of point of care testing (POCT) in the autopsy setting, Ginn et al. noted potential urine dipstick applications, including biochemical and toxicological analyses [7]. Several papers focused on the use of post-mortem dipstick urinalysis for biochemical analysis. One paper was only available in Korean and could not be evaluated in more detail [8]. In a study including 188 forensic autopsies, Mitchell et al. [9] found a sensitivity of 0.83 and specificity of 0.93 for the detection of high glucose vitreous humor levels (≥ 10 mmol/L). For possible ketoacidosis (vitreous BHB ≥ 5 mmol/L) the sensitivity and specificity were 1 and 0.12, respectively. In a similar study including 59 forensic autopsies, Walta et al. found a sensitivity of 0.89 and specificity of 0.90 for elevated glucose levels (≥ 7 mmol/L). The sensitivity and specificity for possible ketoacidosis (vitreous humor total ketones ≥ 3 mmol/L) were 0.84 and 0.68, respectively [10]. Although informative, these studies have shortcomings. For glucose testing, both included many true negative cases (170/188 for Mitchell et al., 50/59 for Walta et al.), which significantly reduced the power of the studies. Furthermore, Walta et al. grouped the dipstick results into positive and negative, diminishing the differentiating power of the dipstick result. For ketones in particular, 13 this considerably increased the number of false negative urine dipstick results. Neither paper tested interobserver variation. Lastly, neither explored how specif (...truncated)