Annals of Clinical Biochemistry最新文献

BackgroundFaecal immunochemical tests (FIT) detect and quantify faecal haemoglobin (f-Hb) to triage symptomatic primary care patients for the risk of colorectal cancer (CRC).MethodFIT was performed using FOB Gold® on a Siemens ADVIA Chemistry XPT analyser at Stepping Hill Hospital. Diagnostic accuracy was assessed by following up FIT results between June 2023 and June 2024. Results of ≥10 μg of haemoglobin per gram of faeces (µg/g) were considered as positive. The FIT results were matched with data from the Somerset cancer register, concluding if patient had CRC or non-CRC findings.ResultsA total of 12,640 patients were included in this study. Colonoscopies (or contrast CT) were performed on 1476 patients with f-Hb results of ≥10 µg/g and on 617 patients with f-Hb <10 µg/g as the clinician had further concerns. A total of 98 cancers were found (89 had f-Hb ≥10 µg/g and 9 had f-Hb <10 µg/g). The remaining 10,547 with f-Hb <10 µg/g were considered as non-CRC due to lack of follow-up for >6 months. Using the 10 µg/g cut-off, FOB Gold® sensitivity for CRC was 90.8% and the specificity was 88.9%; the positive predictive value was 6.0% and the negative predictive value was 99.9%. The receiver operating characteristic curve had an area under the curve of 0.92 (95% CI 0.89 to 0.95).ConclusionFOB Gold® has comparable diagnostic performance for detecting CRC in symptomatic primary care patients as other FIT systems at 10 µg/g.

BackgroundPneumatic tube systems (PTSs) have revolutionized sample transport efficiency, yet concerns about sample integrity remain unresolved. This study evaluated the AirLab system (PazKorea, Hanam-si, Korea), a novel high-speed carrier-free PTS, for its impact on sample integrity and turnaround time (TAT) under controlled pre-analytical conditions.MethodsBlood specimens were collected in duplicate from 42 participants (30 healthy volunteers and 12 outpatients with chronic alcohol use) and randomly assigned to PTS or manual transport. Multiple laboratory parameters were analysed, including chemistry, hematology, coagulation, and heavy metal tests. Sample integrity was assessed by comparing test results between transport methods using both statistical analysis and clinical significance criteria based on total allowable error (TAE). Pre-analytical, analytical and total TATs were compared between transport methods.ResultsAmong 20 measurands, four showed statistically significant differences: glucose, potassium (K), lactate dehydrogenase (LD), and mean corpuscular volume (MCV). PTS yielded higher results for glucose, K and LD (average percentage biases: 1.88%, 2.01%, and 15.80%, respectively), while producing lower results for MCV (average percentage bias: -0.47%). Only LD showed clinically significant differences, as its average percentage bias exceeded its desirable TAE. PTS significantly reduced both pre-analytical and total TATs for all test types, with reductions ranging from 12.12% to 22.82% and 7.32% to 8.98%, respectively, whereas analytical TATs remained unchanged.ConclusionsThe AirLab system effectively preserves sample integrity for most laboratory parameters while improving operational efficiency through TAT reduction. However, the clinically significant elevation in LD levels necessitates careful interpretation when employing this system in clinical laboratories.

Glycerol kinase deficiency (GKD) is a rare X-linked metabolic disorder often presenting in infancy or childhood. In adults, it may remain undiagnosed due to nonspecific symptoms or incidental biochemical findings. We report a case of incidental GKD diagnosis in an adult male presenting with hyponatraemia and acute kidney injury (AKI). Discrepancies between triglyceride concentrations and lipaemic indices prompted further investigation, revealing severe hyperglycerolaemia due to GKD. This case highlights the importance of considering GKD in adults with unexplained hypertriglyceridaemia, especially when triglyceride concentrations are discordant with lipaemic indices and other lipid profile parameters. Genetic testing confirmed that the patient was hemizygous for a likely pathogenic variant in the GK gene, consistent with a genetic diagnosis of glycerol kinase deficiency.

Strict homoeostatic control of potassium is necessary for normal muscle and neural function, and as a result, hyperkalaemia can be life-threatening and requires timely management. Prior to treating the patient, however, it is important to determine if hyperkalaemic blood test results are authentic and not due to pre-analytical factors as treatment in this context may provoke potentially dangerous hypokalaemia. We present the case of a 47-year-old female referred for further investigation following 2 years of otherwise unexplained intermittent hyperkalaemia. Her highest recorded potassium was 8.9 mmol/L (reference interval: 3.5-5.2 mmol/L). She was otherwise healthy, not on regular medications, and asymptomatic during these episodes. There was no evidence of associated electrocardiogram (ECG) changes. She had been referred to the Emergency Department twice in 6 months due to hyperkalaemia, but these episodes resolved on repeat testing without any intervention. Further investigation revealed a significant time- and temperature-dependent increase in potassium concentration in whole blood samples, compared to a control. ABCB6 single gene testing revealed a heterozygous variant, c.1123 C>T, p. (Arg375Trp), consistent with a diagnosis of familial pseudohyperkalaemia (FP). This is an autosomal dominant condition, which results in increased efflux of potassium from red blood cells at sub-physiological temperatures. Whilst this is an ex vivo phenomenon, unless recognised it poses a clinical risk to patients as they may be treated erroneously.

BackgroundThe rise in serum thyroid stimulating hormone (TSH) in healthy older adults is well established. However, age-related reference intervals are not widely used. We aimed to establish all-adult and age-related reference intervals for TSH, free thyroxine (FT4) and free triiodothyronine (FT3) and determine their impact on primary care thyroid testing results.MethodsWe measured TSH, FT4 and FT3 by Roche Cobas assays in a reference cohort of 1364 anti-thyroid peroxidase antibody negative adults with no self-reported medical conditions or medications. Reference intervals were generated for all-adult, 18-60 and over 60 years. Reference intervals were applied to 21,286 primary care tests with no known thyroid disease to assess effect on test interpretation.ResultsIn the reference cohort, 23.2% were over 60 years compared to 50.4% of those undergoing thyroid testing in primary care. With an all-adult reference interval, 8.2% of over 60s had an elevated TSH, 7.0% were classified as subclinical hypothyroid and 0.8% as overt hypothyroid. With age-related reference intervals, this fell to 4.4% with an elevated TSH, 3.7% subclinical hypothyroid and 0.4% overt hypothyroid. Minimal changes were seen in the 18-60 years group.ConclusionsAn all-adult reference interval derived from healthy and therefore younger individuals is less appropriate for the older subset of the population being tested. Application of an age-related reference interval for over 60s would reduce the proportion of patients with abnormal thyroid test results. In turn, this would decrease potentially unnecessary cascade and repeat testing as well as regular follow-up in primary care.

BackgroundSerum copper is an essential trace element, and accurate quantification is important for assessing copper status in pregnancy and supporting early clinical interventions. However, current serum copper assays face several challenges, including potential inaccuracy, poor comparability between methods, and difficulties in transferring reference intervals (RIs) between populations. This study aimed to establish a simple inductively coupled plasma mass spectrometry (ICP-MS)-based candidate reference method for serum copper to strengthen the reference measurement system, and to verify whether recently proposed multicenter RIs for serum copper can be transferred to a Chinese population.MethodsCobalt was used as the internal standard. After digestion with Optima-grade ultrapure nitric acid, samples were diluted 100-fold with ultrapure water. The ⁶³Cu/⁵⁹Co ratio was measured in helium collision mode, with the gas flow rate set to 5 mL/min. Analytical performance was validated, and serum copper RIs in pregnant and non-pregnant women were subsequently verified.ResultsA candidate reference method was established. The method demonstrated excellent linearity, with a correlation coefficient (R) exceeding 0.99998 over the range 0-13.75 μg/g. The total precision ranged from 0.30% to 0.40%. The spike recovery was 100.06% (99.95-100.14%). Trueness was confirmed by measurements of NIST SRM 1598a, which fell within the certified value and its stated uncertainty. The RI for healthy non-pregnant women was transferable to healthy Chinese women, whereas the pregnancy-specific RI for serum copper was not fully transferable and requires further adjustment for Chinese women.ConclusionA highly sensitive and specific candidate reference method for serum copper was established, strengthening the reference measurement system and contributing to the standardization and harmonization of serum copper assays. Pregnancy-specific RIs for serum copper in Chinese women should be established.