A single faecal bile acid stool test demonstrates potential efficacy in replacing SeHCAT testing for bile acid diarrhoea in selected patients.

This study examines the validity of measuring faecal bile acids (FBA) in a single stool sample as a diagnostic tool for bile acid diarrhoea (BAD) by direct comparison to the 75selenium-homotaurocholic acid (SeHCAT) scan. A prospective observational study was undertaken. Patients with chronic diarrhoea (> 6 weeks) being investigated for potential BAD with SeHCAT scan provided stool samples for measurement of FBA, using an enzyme-linked immunosorbent assay. Patients were characterised into four groups: SeHCAT negative control group, post-cholecystectomy, idiopathic BAD and post-operative terminal ileal resected Crohn's disease. Stool samples were collected at baseline and 8-weeks post treatment to determine whether FBA measurement could be used to monitor therapeutic response. 113 patients had a stool sample to directly compare with their SeHCAT result. FBA concentrations (µmol/g) and interquartile ranges in patients in the control group (2.8; 1.6-4.2), BAD (3.6; 1.9-7.2) and post-cholecystectomy cohort 3.8 (2.3-6.8) were similar, but all were significantly lower (p < 0.001) compared to the Crohn's disease cohort (11.8; 10.1-16.2). FBA concentrations in patients with SeHCAT retention of < 15% (4.95; 2.6-10.5) and < 5% (9.9; 4.8-15.4) were significantly higher than those with a SeHCAT retention > 15% (2.6; 1.6-4.2); (p < 0.001 and p < 0.0001, respectively). The sensitivity and specificity using FBA cut-off of 1.6 µmol/g (using ≤ 15% SeHCAT retention as diagnostic of BAD) were 90% and 25% respectively. A single random stool sample may have potential use in diagnosing severe BAD or BAD in Crohn's patients. Larger studies are now needed to confirm the potential efficacy of this test to accurately diagnose BAD in the absence of SeHCAT testing.

kEDTA Sample Contamination: A Reappraisal.

BACKGROUND: Potassium EDTA (kEDTA) contamination of serum samples is common, causing spurious hyperkalemia, hypozincemia, and hypocalcemia that if unrecognized may adversely affect patient care. Gross kEDTA contamination is easy to detect, but identification of spurious electrolytes due to small amounts of contamination requires measurement of serum EDTA. We validated an EDTA assay on the Abbott Architect and reassessed its value in identifying kEDTA contamination and in studying mechanisms for contamination. METHODS: Within- and between-batch imprecision, linearity, recovery, interference, and carryover were assessed. Serum supplemented with k2EDTA plasma, to mimic sample contamination, was used to study its effect on potassium, calcium, zinc, magnesium, and alkaline phosphatase. Our current laboratory protocol for identification of kEDTA contamination, based on measurement of serum calcium, was compared to that of EDTA measurement. RESULTS: The EDTA assay displayed acceptable performance characteristics. Hemoglobin was a positive interferent. EDTA was detectable in serum contaminated with 1% (v:v) k2EDTA plasma. An increase in serum potassium of 0.54 mmol/L (11.9%) was observed at a measured EDTA concentration of 0.19 mmol/L, equivalent to 3.2% (v:v) contamination. At this EDTA concentration reductions were also observed in zinc (71%), calcium (1%), alkaline phosphatase (ALP) (4%), and magnesium (2.4%). The serum EDTA assay detected contamination in 31/106 patient samples with hyperkalemia (potassium ≥6.0mmol/L), 20 of which were undetected by the current laboratory protocol. CONCLUSIONS: The EDTA assay displayed acceptable performance, with the ability to reliably measure EDTA at low concentrations. Only a small amount of kEDTA causes significant spurious hyperkalemia and is only reliably detected with EDTA measurement.

Acute adrenal failure: a potentially fatal consequence of an adulterated herbal remedy.

Herbal remedies adulterated with glucocorticoids can cause Cushing's syndrome. We report a severe presentation of a 'herbal remedy' adulterated with glucocorticoids; causing a potentially fatal adrenal crisis precipitated by acute illness. Investigations were consistent with adrenal suppression and confirmed, after tablet analysis, to be due to a 'herbal remedy' containing synthetic betamethasone/dexamethasone. This case highlights the need for clinical vigilance and patient education about the potential risks associated with the use of unlicensed treatments and the role of tablet analysis in routine biochemistry.

Post-thyroidectomy hypocalcemia: Impact on length of stay.

Hypocalcemia is a recognized complication following thyroid surgery. Variability in the definition of hypocalcemia and different opinions on its management can lead to unnecessary patient morbidity and longer hospital stays as a result of inappropriate or untimely treatment. Therefore, we developed a management guideline for the recognition and treatment of post-thyroidectomy hypocalcemia, and we conducted a retrospective study to assess its impact on length of stay (LOS). Between April 1, 2007, and March 31, 2009, 29 adults had undergone a total or completion thyroidectomy at our large district general hospital. Of this group, postoperative hypocalcemia (defined as a serum calcium level of <2.00 mmol/L) developed in 13 patients (44.8%) during the first 3 postoperative days. Our guideline went into effect on July 1, 2009, and from that date through June 30, 2010, 18 more adults had undergone a total or completion thyroidectomy. Of that group, hypocalcemia developed in 7 patients (38.9%); the guideline was actually followed in 5 of these 7 cases (71.4%). In the preguideline group, the development of hypocalcemia increased the mean LOS from 2.0 days to 7.0 days (p < 0.001). The management of postoperative hypocalcemia in these cases was highly variable and was dictated by variations in practice rather than patient needs. In the postguideline group, postoperative hypocalcemia increased the mean LOS from 2.7 days to only 3.7 days (p = 0.07). While the difference between LOS in the two hypocalcemic groups did not reach statistical significance, we believe it merely reflects the relatively small number of patients rather than any lack of guideline efficacy. The implementation of a simple flowchart guideline for the management of postoperative hypocalcemia in our hospital has resulted in more uniform management and a reduced LOS.