The frequency of testing for glycated haemoglobin, HbA1c, is linked to the probability of achieving target levels in patients with suboptimally controlled diabetes mellitus.

Background We previously showed, in patients with diabetes, that >50% of monitoring tests for glycated haemoglobin (HbA1c) are outside recommended intervals and that this is linked to diabetes control. Here, we examined the effect of tests/year on achievement of commonly utilised HbA1c targets and on HbA1c changes over time. Methods Data on 20,690 adults with diabetes with a baseline HbA1c of >53 mmol/mol (7%) were extracted from Clinical Biochemistry Laboratory records at three UK hospitals. We examined the effect of HbA1c tests/year on (i) the probability of achieving targets of ≤53 mmol/mol (7%) and ≤48 mmol/mol (6.5%) in a year using multi-state modelling and (ii) the changes in mean HbA1c using a linear mixed-effects model. Results The probabilities of achieving ≤53 mmol/mol (7%) and ≤48 mmol/mol (6.5%) targets within 1 year were 0.20 (95% confidence interval: 0.19-0.21) and 0.10 (0.09-0.10), respectively. Compared with four tests/year, having one test or more than four tests/year were associated with lower likelihoods of achieving either target; two to three tests/year gave similar likelihoods to four tests/year. Mean HbA1c levels were higher in patients who had one test/year compared to those with four tests/year (mean difference: 2.64 mmol/mol [0.24%], p<0.001). Conclusions We showed that ≥80% of patients with suboptimal control are not achieving commonly recommended HbA1c targets within 1 year, highlighting the major challenge facing healthcare services. We also demonstrated that, although appropriate monitoring frequency is important, testing every 6 months is as effective as quarterly testing, supporting international recommendations. We suggest that the importance HbA1c monitoring frequency is being insufficiently recognised in diabetes management.

Reduced testing frequency for glycated hemoglobin, HbA1c, is associated with deteriorating diabetes control.

OBJECTIVE: We previously showed that in patients with diabetes mellitus, glycated hemoglobin (HbA1c) monitoring outside international guidance on testing frequency is widespread. Here we examined the relationship between testing frequency and diabetes control to test the hypothesis that retest interval is linked to change in HbA1c level. RESEARCH DESIGN AND METHODS: We examined repeat HbA1c tests (400,497 tests in 79,409 patients, 2008-2011) processed by three U.K. clinical laboratories. We examined the relationship between retest interval and 1) percentage change in HbA1c and 2) proportion of cases showing a significant HbA1c rise. The effect of demographics factors on these findings was also explored. RESULTS: Our data showed that the optimal testing frequency required to maximize the downward trajectory in HbA1c was four times per year, particularly in those with an initial HbA1c of ≥7% (≥53 mmol/mol), supporting international guidance. Testing 3-monthly was associated with a 3.8% reduction in HbA1c compared with a 1.5% increase observed with annual testing; testing more frequently provided no additional benefit. Compared with annual monitoring, 3-monthly testing was associated with a halving of the proportion showing a significant rise in HbA1c (7-10 vs. 15-20%). CONCLUSIONS: These findings provide, in a large, multicenter data set, objective evidence that testing outside guidance on HbA1c monitoring frequency is associated with a significant detrimental effect on diabetes control. To achieve the optimum downward trajectory in HbA1c, monitoring frequency should be quarterly, particularly in cases with suboptimal HbA1c. While this impact appears small, optimizing monitoring frequency across the diabetes population may have major implications for diabetes control and comorbidity risk.

An automated minimum retest interval rejection rule reduces repeat CRP workload and expenditure, and influences clinician-requesting behaviour.

AIMS: Repeat serum C-reactive protein (CRP) measurements on the same day or on consecutive days are of limited clinical value. Minimum retesting intervals are recommended for managing unnecessary repeat testing. As not previously reported, we studied the effect of minimum retesting interval test rejection on laboratory workload and expenditure and on clinician-requesting behaviour. METHODS: In a prospective study, we evaluated the effect of an automated 48 h CRP minimum retesting interval rule on inpatient and outpatient CRP workload and costs. Control data on inpatient and outpatient serum urea and electrolytes (UE) workload were collected during the study. RESULTS: Over 1 year, there was a 7.0% and 12.3% decrease in CRP requests and CRP tests analysed, respectively, following the introduction of the minimum retesting interval rule when compared to the 1 year baseline period. This equated to an estimated annual reduction in revenue costs of £10 500, but cash savings in consumable costs of £3000. There was no significant change in UE requests. CONCLUSIONS: We report, for the first time, that automated minimum retesting interval rejection rules as a stand-alone strategy are a cheap and sustainable method for reducing unnecessary repeat CRP tests, resulting in small laboratory cash savings, more efficient use of laboratory resources and standardisation of patient care pathways. The minimum retesting interval rejection rule also altered clinician test-requesting behaviour towards more appropriate requesting.

The effect of the systemic inflammatory response, as provoked by elective orthopaedic surgery, on serum uric acid in patients without gout: a prospective study.

OBJECTIVE: Acute gout is associated with a decrease in serum uric acid (SUA) that is considered to be in response to acute inflammation but it may be a feature of gout itself. We, therefore, aimed to investigate the effect of the acute systemic inflammatory response (SIR) on SUA concentrations in subjects without gout. METHODS: SUA and urinary excretion of uric acid (UA) (expressed as fractional excretion of UA; FEua%) were measured in 30 patients before and 48 h after elective knee or hip surgery. The SIR was assessed by measuring serum CRP and urine microalbumin excretion [expressed as the albumin-creatinine ratio (ACR)] before and after surgery in the same patients. RESULTS: The mean (s.d.) serum CRP increased following surgery [5.0 (5.5) vs 116.0 (81.2) mg/l; P < 0.0001) as did urine ACR [0.85 (1.03) vs 2.10 (2.60) mg/mmol; P = 0.004]. SUA decreased following surgery [312 (64) vs 282 (82) µmol/l; P = 0.0033] but FEua% was unchanged [6.4 (2.3) vs 7.3 (3.3)%; P = 0.1726]. CONCLUSION: The SIR is associated with a decrease in SUA concentrations in normouricaemic patients without gout. The decrease in SUA concentrations is not due to increased urinary excretion of UA. This study supports the notion that the decrease in SUA during acute gout is due to the associated SIR rather than gout per se.

Multi-centre observational study of spurious hyperkalaemia due to EDTA contamination.

BACKGROUND: A multi-centre observational study investigating the prevalence of spurious hyperkalaemia due to potassium ethylenediaminetetraacetic acid (kEDTA) contamination. METHODS: Serum EDTA was measured in anonymised serum samples with a serum potassium > 6.0 mmol/L collected over a one month period in five different hospital laboratories. Two of the participating laboratories routinely screen all hyperkalaemic samples for EDTA contamination. RESULTS: EDTA contamination was present in 4.1% (range 1.2%-6.7%) of hyperkalaemic samples. In three laboratories, without routine EDTA screening, 50% "EDTA contaminated" were identified by laboratory staff, the remaining 50% samples were undetected and reported as genuine hyperkalaemia. In these laboratories, EDTA was not measurable in 2 samples reported as "EDTA contaminated". CONCLUSIONS: Spurious hyperkalaemia due to kEDTA contamination is relatively common. Education regarding correct blood collection technique offers the best strategy in preventing EDTA sample contamination. Gross kEDTA contamination is easily identified by laboratory staff in samples with marked unexpected hyperkalaemia and hypocalcaemia. Spurious hyperkalaemia due to modest kEDTA contamination may only be confidently detected by measurement of serum EDTA.