Utilization of five data mining algorithms combined with simplified preprocessing to establish reference intervals of thyroid-related hormones for non-elderly adults.

BACKGROUND: Despite the extensive research on data mining algorithms, there is still a lack of a standard protocol to evaluate the performance of the existing algorithms. Therefore, the study aims to provide a novel procedure that combines data mining algorithms and simplified preprocessing to establish reference intervals (RIs), with the performance of five algorithms assessed objectively as well. METHODS: Two data sets were derived from the population undergoing a physical examination. Hoffmann, Bhattacharya, Expectation Maximum (EM), kosmic, and refineR algorithms combined with two-step data preprocessing respectively were implemented in the Test data set to establish RIs for thyroid-related hormones. Algorithm-calculated RIs were compared with the standard RIs calculated from the Reference data set in which reference individuals were selected following strict inclusion and exclusion criteria. Objective assessment of the methods is implemented by the bias ratio (BR) matrix. RESULTS: RIs of thyroid-related hormones are established. There is a high consistency between TSH RIs established by the EM algorithm and the standard TSH RIs (BR = 0.063), although EM algorithms seems to perform poor on other hormones. RIs calculated by Hoffmann, Bhattacharya, and refineR methods for free and total triiodo-thyronine, free and total thyroxine respectively are close and match the standard RIs. CONCLUSION: An effective approach for objectively evaluating the performance of the algorithm based on the BR matrix is established. EM algorithm combined with simplified preprocessing can handle data with significant skewness, but its performance is limited in other scenarios. The other four algorithms perform well for data with Gaussian or near-Gaussian distribution. Using the appropriate algorithm based on the data distribution characteristics is recommended.

Establishment of Early Pregnancy Related Thyroid Hormone Models and Reference Intervals for Pregnant Women in China Based on Real World Data.

Thyroid hormone reference intervals are crucial for diagnosing and monitoring thyroid dysfunction during early pregnancy, and the dynamic change trend of thyroid hormones during pregnancy can assist clinicians to assess the thyroid function of pregnant women. This study aims to establish early pregnancy related thyroid hormones models and reference intervals for pregnant women. We established two derived databases: derived database* and derived database#. Reference individuals in database* were used to establish gestational age-specific reference intervals for thyroid hormones and early pregnancy related thyroid hormones models for pregnant women. Individuals in database# were apparently healthy non-pregnant women. The thyroid hormones levels of individuals in database# were compared with that of individuals in database* using nonparametric methods and the comparative confidence interval method. The differences in thyroid stimulating hormone and free thyroxine between early pregnant and non-pregnant women were statistically significant (p<0.0001). The reference intervals of thyroid stimulating hormone, free thyroxine and free triiodothyronine for early pregnant women were 0.052-3.393 µIU/ml, 1.01-1.54 ng/dl, and 2.51-3.66 pg/ml, respectively. Results concerning thyroid stimulating hormone and free thyroxine reference intervals of early pregnancy are comparable with those from other studies using the same detection platform. Early pregnancy related thyroid hormones models showed various change patterns with gestational age for thyroid hormones. Early pregnancy related thyroid hormones models and reference intervals for pregnant women were established, so as to provide accurate and reliable reference basis for the diagnosing and monitoring of maternal thyroid disfunction in early pregnancy.

Plasma or serum, which is the better choice for the measurement of metanephrines?

Measurement of metanephrines (MNs: metanephrine [MN] and normetanephrine [NMN]) is recommended for the initial biochemical diagnosis of pheochromocytoma and paraganglioma. Despite some drawbacks, plasma is commonly used for sampling. Here, we determined the feasibility of using serum, as an alternative to plasma, by comparing MNs in plasma and serum and evaluating the stability of MNs in serum. MNs obtained from serum, EDTA plasma, and heparin plasma were measured using LC-MS/MS immediately or after storage at 4 °C for 24 h, 72 h, and 7 days, and at -80 °C for 7 days, after sample collection. The differences between sample stability at given time points were compared using one-way ANOVA and Students' paired t-test, and the mean percent deviation was compared with total change limit (TCL). No significant difference was observed in MN and NMN between serum and EDTA plasma, and the mean percent deviation of the results obtained from serum compared to that from EDTA plasma was within the TCL. However, the difference of MN between EDTA plasma and heparin plasma exceeded the TCL. Both MNs in EDTA plasma and heparin plasma showed a significant decreasing trend at 4 °C with time (p < .01), while those in serum were relatively stable, with the mean percent deviation not exceeding the TCL at any time point or temperature. In conclusion, MNs measurement did not significantly differ between EDTA plasma and serum when measured immediately after collection, and MNs in serum were more stable than that in plasma.

Establishing reference intervals for vitamins A and E in Chinese elderly people using liquid chromatography-tandem mass spectrometry.

BACKGROUND: Vitamins A and E play important roles in sustaining life activities and maintaining a good physical condition. However, most people, particularly the elderly, experience micronutrient deficiencies. This study aimed to establish reference intervals (RIs) for vitamins A and E in Chinese elderly people using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. METHODS: A total of 356 apparently healthy individuals aged ≥64 years who underwent health checkups were randomly selected for the study. Vitamin A and E levels were measured using LC-MS/MS. The effect of sex on vitamin A and E levels was evaluated, and RIs were established using a parametric method. RESULTS: Females showed significantly higher levels of vitamin E than males (p < 0.05). However, no significant sex-specific difference was observed with vitamin A levels. The RI for vitamin A in the elderly was 0.283-0.730 mg/L. For vitamin E, the RIs were 4.39-15.63, 4.51-16.14, and 4.41-14.67 mg/L for the total, female, and male participants, respectively. In multiple linear regression, alanine aminotransferase, glutamyl transpeptidase, urea, glucose, and uric acid levels increased with increasing vitamin A levels (p < 0.05), and total cholesterol and low-density lipoprotein cholesterol levels increased with increasing vitamin E levels (p < 0.05). Direct bilirubin levels decreased with increasing vitamin E levels (p < 0.05). CONCLUSIONS: This study established RIs for vitamins A and E in Chinese elderly individuals using an LC-MS/MS method. We also found that females had significantly higher vitamin E levels than males. The findings could provide a scientific basis for interpreting vitamin status in the elderly.

The effect of ALDH2 rs671 gene mutation on clustering of cardiovascular risk factors in a big data study of Chinese population: associations differ between the sexes.

BACKGROUND: The ALDH2 rs671 genetic polymorphism has been linked with cardiovascular diseases (CVDs), but comprehensive epidemiological studies are lacking. An observational, retrospective big data study was carried out to evaluate the associations between this polymorphism and clustering cardiovascular risk factors (CRFs) in a Chinese population. METHODS: A total of 13,101 individuals (8431 males and 4670 females) were enrolled. Genetic polymorphism was assessed using gene mutation detection kits, coupled with an automatic fluorescent analyzer. Other data were obtained from the records of the Department of Health Care at Peking Union Medical College Hospital. RESULTS: Comparing the concentrations of common biochemical analytes, including BMI, SBP, DBP, ALT, AST, γ-GT, TBil, Cr, Glu, TC, TG, and HDL-C among individuals with the GG, GA, and AA genotypes of ALDH2 rs671, we found significant differences in males (all p < 0.001), but not in females. For males, the frequencies of hypertension, diabetes, and obesity were significantly higher for GG than for GA or AA (all p < 0.05). However, there was no significant difference for dyslipidemia, and no significant associations were observed for all frequencies in females. The prevalence of individuals with 1-4 CRFs was significantly higher among GG males than those carrying GA or AA, and fewer GG males had non-CRFs (all p < 0.05). CONCLUSION: Polymorphisms of ALDH2 rs671 are associated with clustering CRFs, especially hypertension and diabetes in males, but not in females. These associations are likely mediated by alcohol intake, which is also associated with this gene.

Establishment of variation source and age-related reference interval models for 22 common biochemical analytes in older people using real-world big data mining.

BACKGROUND: the ageing population has increased in many countries, including China. However, reference intervals (RIs) for older people are rarely established because of difficulties in selecting reference individuals. Here, we aimed to analyse the factors affecting biochemical analytes and establish RI and age-related RI models for biochemical analytes through mining real-world big data. METHODS: data for 97,220 individuals downloaded from electronic health records were included. Three derived databases were established. The first database included 97,220 individuals and was used to build age-related RI models after identifying outliers by the Tukey method. The second database consisted of older people and was used to establish variation source models and RIs for biochemical analytes. Differences between older and younger people were compared using the third database. RESULTS: sex was the main source of variation of biochemical analytes for older people in the variation source models. The distributions of creatinine and uric acid were significantly different in the RIs of biochemical analytes for older people established according to sex. Age-related RI models for biochemical analytes that were most affected by age were built and visualized, revealing various patterns of changes from the younger to older people. CONCLUSION: the study analysed the factors affecting biochemical analytes in older people. Moreover, RI and age-related RI models of biochemical analytes for older people were established to provide important insight into biological processes and to assist clinical use of various biochemical analytes to monitor the status of various diseases for older people.

Short-term biological variation and Reference change values of urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydroguanosine.

AIM: The DNA and RNA oxidative damage products urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-odGsn) and 8-oxo-7,8-dihydroguanosine (8-oGsn) have potential use in clinical practice. However, biological variation (BV) and reference change values (RCVs) have not been established. The aim of this study was to establish the short-term between-subject BV(CVG ), within-subject BV(CVI ), and RCVs for urinary 8-odGsn and 8-oGsn. METHODS: First-morning midstream urine specimens were collected from 20 apparently healthy subjects(ten males and ten females) on five consecutive days. 8-odGsn and 8-oGsn were measured using LC-MS/MS, while urine creatinine (U-Cr) was also measured to correct their results. A two-level nested ANOVA was used to estimate the CVI and CVG. RESULTS: The values of CVG for 8-odGsn, 8-odGsn/U-Cr, 8-oGsn, and 8-oGsn/U-Cr were 31.2%, 39.6%, 35.3%, and 28.8%, respectively, while CVI for them were 40.5%, 9.0%, 33.5%, and 12.1%, respectively. The RCVs for 8-odGsn, 8-odGsn/U-Cr, 8-oGsn, and 8-oGsn/U-Cr were 112.5%, 26.7%, 93.7%, and 36.5%, respectively. CONCLUSION: BV and RCVs were firstly established for 8-oxo-dGsn and 8-oGsn, and can be used in clinical practice.

Comparison of three different chemiluminescence assays and a rapid liquid chromatography tandem mass spectrometry method for measuring serum aldosterone.

Background This study aimed to quantify and compare serum aldosterone (sALD) levels through three different chemiluminescence immunoassays (CLIAs) and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. Methods Serum samples from 221 patients with suspected primary aldosteronism (PA) were retrospectively included in this study conducted at the Peking Union Medical College Hospital from June to August in 2017. sALD levels were determined using the LC-MS/MS method and three different CLIA systems, viz., DiaSorin® XL, iSYS and Auto Lumo A2000. Pooled fresh serum samples were used for recalibration. Passing-Bablok regression analysis, correlation matrix, and Bland-Altman plots were used to evaluate the concurrence among ALD levels determined using the three CLIAs. Results Within-laboratory precision of the four assays ranged from 2.1% to 9.4%, except the coefficient variation (CV) of one of the CLIAs, which exceeded 20.0% for samples with low sALD levels. sALD levels determined using LC-MS/MS were significantly lower than those determined using the other three CLIAs (p < 0.0001). Spearman's correlation coefficient of the four assays ranged from 0.745 to 0.950 (p < 0.0001). The Bland-Altman plot showed that the average bias (%) for the three CLIAs and LC-MS/MS ranged from -69.3 to -49.2. After recalibration, this correlation did not improve among the assays. However, the bias and bias percentage at the medical decision level improved between LC-MS/MS and DiaSorin® XL/iSYS. Conclusions Significant inconsistencies between the results of CLIAs and LC-MS/MS indicate that different sALD measures cannot be used interchangeably.

Reference intervals for thyroid-stimulating hormone, free thyroxine, and free triiodothyronine in elderly Chinese persons.

Background Thyroid hormone levels are essential for diagnosing and monitoring thyroid diseases. However, their reference intervals (RIs) in elderly Chinese individuals remain unclear. We aimed to identify factors affecting thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels using clinical "big data" to establish hormone level RIs for elderly Chinese individuals. Methods We examined 6781, 6772, and 6524 subjects aged ≥65 years who underwent FT3, FT4, and TSH tests, respectively, at the Peking Union Medical College Hospital between September 1, 2013, and August 31, 2016. Hormones were measured using an automated immunoassay analyzer (ADVIA Centaur XP). RIs were established using the Clinical Laboratory Standards Institute document C28-A3 guidelines. Results The median TSH was significantly higher in women than in men; the opposite was true for median FT3 and FT4 levels. No differences were observed in TSH or FT4 by age in either sex or overall; FT3 levels significantly decreased with age. Seasonal differences were observed in TSH and FT3 levels but not FT4 levels; the median TSH was the highest in winter and lowest in summer, whereas the median FT3 was the lowest in summer (albeit not significantly). RIs for TSH were 0.53-5.24 and 0.335-5.73 mIU/L for men and women, respectively; those for FT3 were 3.76-5.71, 3.60-5.42, and 3.36-5.27 pmol/L in 64- to 74-, 75- to 84-, and 85- to 96-year-old subjects, respectively. The RI for FT4 was 11.70-20.28 pmol/L. Conclusions RIs for TSH in elderly individuals were sex specific, whereas those for FT3 were age specific.

Effect of sampling time on estimates of thyroid-stimulating hormone, free thyroxine, and free triiodothyronine levels.

Despite the need for precise measurement of thyroid hormones levels for disease detection and monitoring, the importance of sampling time for the accuracy of widely used assays is unclear. In this study, the effects of the time of day on thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels were retrospectively evaluated using data obtained from the Laboratory Information System of Peking Union Medical College Hospital. TSH concentrations were significantly lower, and FT4 and FT3 concentrations were higher in males than in females (all p < .05). TSH decreased from 7 am to 1 pm and increased from 1 pm to 4 pm. FT3 concentrations differed among sampling time groups (p < .05). Compared to those at 7 am, the deviations in TSH, FT4, and FT3 were -24.53% to -7.41%, -0.84% to 0.84%, and -0.66% to 0.33%, respectively. TSH levels fluctuated during the day but FT4, FT3 did not exhibit a circadian rhythm. The time of sample collection must be standardized for TSH measurements.

Measuring lipoprotein-associated phospholipase A2 activity in China: Protocol comparison and recalibration.

BACKGROUND: Lp-PLA2 is a novel inflammation marker in cardiovascular disease. While several manufactures have registered Lp-PLA2 activity reagents, few studies have investigated the consistency among these assays. In this study, we compared and recalibrated Lp-PLA2 activity assays. METHODS: Serum samples from 110 patients and 140 healthy individuals were collected for method comparison and reference interval validation, respectively. Fresh human serum pools (847 and 442 U/L) were used for recalibration. Lp-PLA2 activity was analyzed using all five assays with a Beckman AU 5800 analyzer. Passing-Bablok regression equations and Bland-Altman plots were used to estimate the relationship and bias among the results. A 2.5% confidence interval (CI) and 97.5% CI were used to establish a laboratory reference interval. RESULTS: Assay imprecision varied from 0.8%-2.9%, while the overall coincidence rates ranged from 75.5%-98.2%. Passing-Bablok regression shows excellent linear correlation between Evermed and Diasys (R2  = 0.999), while that between Diazyme and Evermed was poor (R2  = 0.846). The R2 and correlation coefficient r among assays were 0.846-0.999 and 0.8947-0.9993, respectively. The mean bias percentages ranged from -71.5%-1.6% and -2.0%-11.6% before and after recalibration. As Diazyme and Diasys were not comparable, the Diazyme assay was not recalibrated. The reference intervals determined for Diasys, Evermed, Hengxiao, and Zybio were 184-605, 208-704, 81-328, and 273-696 U/L, respectively. CONCLUSIONS: Our results indicate that recalibration increased assay agreement and also highlight the need for each laboratory to establish its own reference interval for Lp-PLA2 activity.

Iodine status of euthyroid adults: A cross-sectional, multicenter study.

BACKGROUND: Iodine, an essential nutrient, is the most important trace element in thyroid hormone synthesis and maintenance of thyroid function. This study investigated the iodine nutrition status in healthy Chinese adults and assessed the relationship between urinary iodine concentration (UIC) and thyroid hormone levels. METHODS: A cross-sectional, multicenter study was conducted between October 2017 and January 2018, with 1017 adults recruited from five cities in China. All subjects underwent thyroid ultrasonography, and only those with normal results were included in the study. UICs were measured by inductively coupled plasma mass spectroscopy and adjusted using urine creatinine levels. Thyroid hormone levels were measured using an automated immunoassay analyzer. RESULTS: The median UIC and adjusted UIC were 134.0 µg/L and 114.2 µg/g, respectively. UIC was not significantly different between males and females (P = 0.737). However, the adjusted UIC was significantly different between sexes (P < 0.001). The median UIC was higher than 100 µg/L. According to the World Health Organization criterion (100 µg/L), the total prevalence of iodine deficiency is 33.1% (n = 271). The prevalence rates of iodine deficiency in our study were 33.2% and 32.9% in males and females, respectively, and had no difference between sexes and among cities (P > 0.05). Serum thyroid-stimulating hormone (TSH) levels increased when UIC increased. The Kruskal-Wallis test showed no significant differences in free triiodothyronine, free thyroxine, and TSH, with different levels of UIC (all P > 0.05). CONCLUSIONS: Chinese adults with normal thyroid structure have relatively sufficient iodine levels.

Is it necessary for all samples to quantify 25OHD2 and 25OHD3 using LC-MS/MS in clinical practice?

BACKGROUND: The demand for vitamin D testing is increasing in China. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) immunoassay is specific and accurate but requires expensive equipment, experienced operators, and complicated pretreatment of serum. Automated immunoassays are simple and convenient but only determine total 25-hydroxyvitamin D (25OHD). The objective of this study was to quantify 25OHD2 and 25OHD3 in patients to assist clinical physicians and laboratory directors in choosing the most appropriate method to determine 25OHD. METHODS: Vitamin D testing was conducted for 23,695 patients in Peking Union Medical College Hospital from May 2015 to January 2017. Using this large data set, the prevalence and levels of 25OHD2 were analyzed. LC-MS/MS was used to separately determine 25OHD2 and 25OHD3. RESULTS: 25OHD2 (≥2.5 ng/mL) was detected in 16.4% (3877/23,695) of patients. Males had a significantly lower incidence of detectable 25OHD2 (p<0.01); 1077 (13.9%) samples contained detectable 25OHD2 (median: 3.7 ng/mL; 2.5%-97.5%: 2.5-17.2 ng/mL). For females, 2800 (17.5%) samples contained detectable 25OHD2 (median: 4.0 ng/mL; range: 2.5-20.6 ng/mL). Of the 3877 patients with detectable 25OHD2, males had a significantly higher level of 25OHD3 (p<0.01). There was no significant difference in total 25OHD. The proportion of 25OHD2 in total 25OHD was 1.3%-100%; 87.5% (3391/3877) of the samples contained <10 ng/mL 25OHD2. 25OHD2 negatively correlated with 25OHD3 (r=-0.197, p<0.01) and positively correlated with total 25OHD (r=0.217, p<0.01). CONCLUSIONS: Prevalence of 25OHD2 in patients tested for vitamin D is relatively high in China. 25OHD2 is significantly negatively correlated with 25OHD3.

Establishing reference intervals for sex hormones and SHBG in apparently healthy Chinese adult men based on a multicenter study.

BACKGROUND: Measuring sex hormones is essential in diagnosing health issues such as testicular dysfunction, male infertility and feminization syndrome. However, there are no reports on reference intervals (RIs) in Chinese men. We conducted a nationwide multicenter study to establish RIs for seven sex hormones (luteinizing hormone [LH], follicle-stimulating hormone [FSH], prolactin [PRL], total testosterone [TT], free testosterone [FT], bioavailable testosterone [BAT] and estrogen [E2]), as well as sex hormone-binding globulin (SHBG). METHODS: In 2013, 1043 apparently healthy adult men from five representative cities in China (Beijing, Hangzhou, Guangzhou, Dalian and Urumqi) were recruited; hormones were measured using an automated immunoassay analyzer. Multiple regression analysis (MRA) was performed to identify sources of variation (SVs) that might influence the hormone serum levels. RIs were computed using the parametric method. RESULTS: Dalian and Hangzhou had significantly higher E2 values than other cities; age was a major source of variation for FSH, LH, PRL, SHBG, FT and BAT. FSH, LH and SHBG increased significantly with age, while PRL, FT and BAT decreased with age. TT showed no significant age-related changes. Median (RIs) derived without partition by age were as follows: FSH, 5.6 (1.9-16.3) IU/L; LH, 4.2 (1.6-10.0) IU/L; PRL, 189 (88-450) mIU/L; E2, 85 (4.7-195) pmol/L; SHBG, 29.4 (11.5-66.3) nmol/L; TT, 15.6 (7.4-24.5) nmol/L; FT, 0.31 (0.16-0.52) nmol/L; and BAT, 8.0 (3.7-13.2) nmol/L. RIs were also derived in accordance with between-city and between-age differences. CONCLUSIONS: RIs were established for sex hormones and SHBG in apparently healthy Chinese men in consideration of age.

Validation of a simple inductively coupled plasma mass spectrometry method for detecting urine and serum iodine and evaluation of iodine status of pregnant women in Beijing.

Rapid and simple method for serum and urine iodine is necessary for iodine-related diseases. This study aimed to establish and validate a simple and rapid method for quantification of iodine in human urine and serum using inductively coupled plasma mass spectrometry (ICP-MS). Generally, samples were diluted using water with 1.5% isopropanol and 7 mmol hydrous ammonium before analysis by the ICP-MS. Performance of the method was validated, and the urine and serum iodine levels of 72 pregnant women were analyzed. Results showed that the lower limit of detection of the ICP-MS method was 0.87 µg/L. No significant memory effects were observed. Recovery in both serum and urine was approximately 100%. Compared with NIST SRM3668, bias was <1%, exhibiting good accuracy. The inter-run coefficients of variation (CVs) for serum and urine iodine were 2.8-3.5% and 3.5-6.7%, respectively, and total CVs for serum and urine iodine were 3.2-3.7% and 3.9-6.7%, respectively. Comparison of the iodine results obtained by the ICP-MS method and the conventional S-K method revealed excellent correlation (r = 0.984, mean bias = -1.7%). The median urine iodine of pregnant women (125.5 µg/L) was lower than that of WHO criteria for iodine deficiency (median urinary iodine <150 µg/L) while 55.6% of the individuals with urine iodine level less than 150 µg/L. The median serum iodine level of the pregnant women was 69.0 µg/L. In conclusion, a rapid and simple ICP-MS method for urine and serum iodine measurements has been established and validated, and the pregnant women in Beijing may still suffer from insufficient iodine intake. Abbreviations CV coefficients of variation HPLC high-performance liquid chromatography ICP-MS inductively coupled plasma mass spectrometry KED kinetic energy discrimination KI potassium iodide LOD limit of detection S-K Sandell-Kolthoff reaction PUMCH Peking Union Medical College Hospital.

Molecular characterization and functional roles of circulating cell-free extrachromosomal circular DNA.

Circular DNA segments isolated from chromosomes are known as extrachromosomal circular DNA (eccDNA). Its distinct structure and characteristics, along with the variations observed in different disease states, makes it a promising biomarker. Recent studies have revealed the presence of eccDNAs in body fluids, indicating their involvement in various biological functions. This finding opens up avenues for utilizing eccDNAs as convenient and real-time biomarkers for disease diagnosis, treatment monitoring, and prognosis assessment through noninvasive analysis of body fluids. In this comprehensive review, we focused on elucidating the size profiles, potential mechanisms of formation and clearance, detection methods, and potential clinical applications of eccDNAs. We aimed to provide a valuable reference resource for future research in this field.

A comprehensive LC-MS/MS method for the simultaneous measurement of 24 adrenal steroids: From research to clinical practice.

Steroids are essential in the differential diagnosis of congenital adrenal hyperplasia (CAH) subtypes; however, they may confuse physicians with multifarious results. In this study, we established a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous measurement of 24 steroids and developed a steroid metabolite pathway-based report to aid physicians in understanding these results. Solid-phase extraction was used to concentrate and purify target plasma steroids. The linearity, precision, recovery, and matrix effects were thoroughly evaluated. PowerBuilder was used to transfer the results from LC-MS/MS to the graphic report in a laboratory information management system (LIS) and was applied to different subtypes of CAH. Twenty-four steroids were separated and analyzed in one sample preparation and two injections using LC-MS/MS. The linearity of the steroids was excellent, with coefficients of linear regression greater than 0.99. The relative recovery ranged from 90.0 to 107.1 %, whereas the intra- and total coefficient variations were 1.6 âˆ¼ 8.7 % and 2.0 âˆ¼ 9.9 %, respectively. Matrix effects were compensated after internal standard correction. A graphic combination report mode was established and used to effectively identify CAH subtypes. In conclusion, a useful LC-MS/MS method and graphic combination report of 24 steroids based on their metabolite pathways were established.

Asymptomatic elevation of parathyroid hormone levels by antibodies against reagent alkaline phosphatase.

CONTEXT: Although immunoassay interference is a well-known phenomenon, its detection in routine clinical practice remains challenging. Most immunoassay interference can be attributed to the presence of heterophilic or anti-hormone antibodies. However, reports on immunoassay interference specifically related to parathyroid hormone (PTH) are scarce. CASE DESCRIPTION: A 77-year-old woman with hypertension, nephrotic syndrome, and high PTH levels for one year was admitted to our Surgical Department for treatment. The patient had no specific symptoms and normal calcium and alkaline phosphatase (ALP) levels but markedly elevated PTH levels. PTH was 2172 pg/mL using the Beckman Coulter system, whereas the Roche, Abbot, and Siemens systems yielded normal results. PTH concentration decreased to 63.8 pg/mL after pretreatment with polyethylene glycol 6000 and did not decrease to normal levels following pretreatment with heterophilic blocking tube-50 (HBT-50), heterophilic blocking reagent (HBR)-21, or HBR-25. When the HBR-21 concentration was increased, serum PTH decreased to 99.0 pg/mL. After treatment with scavenger bovine alkaline phosphatase (inactive), the concentration of PTH decreased to a normal value (51.3 pg/mL). Additionally, PTH (1-84) concentration was 17.6 pg/mL using LC-MS/MS. CONCLUSION: PTH was falsely evaluated due to anti-bovine ALP antibodies (antibodies against reagent ALP). Anti-bovine ALP antibodies should be considered in assays that use ALP as a signal generator.

Reference intervals for LC-MS /MS measurements of plasma renin activity, aldosterone, angiotensin II, and 24-hour urinary aldosterone in Northern Chinese Han population.

BACKGROUND: Examination of aldosterone to Renin Ratio (ARR) and plasma aldosterone concentration (PAC) or 24-h urinary aldosterone excretion (24-h UALD) was the necessary tests in confirmatory tests for primary aldosteronism (PA). We developed a combined liquid chromatography-tandem mass spectrometry method (LC-MS/MS) for plasma renin activity (PRA), PAC, and angiotensin II (Ang II) and investigated their reference intervals (RIs) in northern Chinese Han population. The RIs of 24-h UALD excretion were also studied using LC-MS/MS. METHODS: A total of 309 healthy volunteers were recruited in 3 cities in China. PRA, PAC, Ang II, and 24-h UALD were measured using the laboratory-developed LC-MS/MS. Multiple linear regression and the variance component model were applied to determine if the RI needed to be split. The RIs of PRA, PAC, and Ang II were determined using the nonparametric percentile method. RESULTS: The laboratory-developed LC-MS/MS method was verified and showed good performance. Standard deviation ratio (SDR) sex for PAC and SDR region for Ang II are 0.466 and 0.407, respectively, indicating that the RIs of PAC and Ang II must be divided by sex and region, respectively. In addition, the SDR 24hUK for 24-h UALD is 0.579, indicating that the RI of 24-h UALD must be partitioned by urine potassium. CONCLUSION: RIs were established for tests related to the renin-angiotensin-aldosterone system in the apparently healthy northern Chinese Han population by the LC-MS/MS method.

Validation and comparison of five data mining algorithms using big data from clinical laboratories to establish reference intervals of thyroid hormones for older adults.

AIM: To establish Reference intervals (RIs) of thyroid-related hormones in older adults using five data mining algorithms and to assess the applicability of each algorithm. METHODS: RIs for thyroid-related hormones in older adults were established using five data mining algorithms based on physical examination and patient data. The results of these algorithms were compared to those of RIs established using healthy older adults recruited following strict inclusion and exclusion criteria. The bias ratio (BR) matrix was used to compare the limits of RIs established using different algorithms. RESULTS: Consistency across different algorithms in physical examination data was found to be greater than that of outpatient data. The transformed Hoffmann, transformed Bhattacahrya, kosmic and refineR algorithms showed good performance in calculating RIs from physical examination data. The RIs of Thyroid Stimulating Hormone (TSH) established using Expectation maximization (EM) and patient data were highly consistent with the RIs established using data from healthy older adults. CONCLUSION: This study recommends the use of transformed Hoffmann, transformed Bhattacahrya, kosmic, and refineR algorithms which are based on physical examination data to establish RIs for thyroid-related hormones in older adults. However, if patient data is used, then an EM algorithm combined with Box-Cox transformation is recommended for data with obvious skewness.