Reference intervals established using indirect method for serum ferritin assayed on Abbott Architect i2000SR analyzer in Chinese adults

B12 deficiency-related glossitis is highly associated with high gastrin-17 and low pepsinogen I

BACKGROUND

The causes of vitamin B12 (B12) deficiency are varied and mainly related to gastric disorders. Glossitis is a common oral manifestation of B12 deficiency and is often first seen by dentists. This study aimed to investigate the correlation between B12 deficiency-related glossitis (B12-def glossitis) and gastric serum biomarkers [gastrin-17(G17), pepsinogen I (PGI), pepsinogen II (PGII), and anti-Helicobacter pylori (H. pylori) antibodies], and preliminarily discuss the etiology of B12-def glossitis.

METHODS

A cross-sectional study was conducted in patients complaining of glossodynia, burning sensation, or severe recurrent oral ulcers, but patients with a history of gastrectomy were excluded. All subjects underwent a uniform oral examination and hematological tests.

RESULTS

Of 243 patients, 133 with B12-def glossitis were in the case group, and 110 with other oral mucosal diseases (non-glossitis) and normal B12 levels were in the control group. In the case group, 84.2% (112/133) showed high G17 and low PGI levels (G17hi PGIlow ). Univariate logistic regression showed that G17hi PGIlow was a high-risk factor for B12-def glossitis (OR: 92.44; 95% CI: 35.91, 238.02). Subgroup analyses in the case group showed that the G17hi PGIlow group presented with lower B12 levels and a lower positive rate of anti-H. pylori antibodies compared to the non-G17hi PGIlow group.

CONCLUSION

Gastric serum biomarkers in patients with B12-def glossitis generally showed G17hi PGIlow , suggesting possible atrophy of gastric corpus and fundus mucosa. The G17hi PGIlow and non-G17hi PGIlow groups may represent different etiologies of B12 deficiency.

Gender-specific association between serum ferritin and neurodevelopment in infants aged 6 to 12 months

Early iron deficiency has detrimental consequences on neurodevelopment; whether male and female infants are equally susceptible to the functional outcomes of iron deficiency is unclear. This study aimed to investigate the sex differences in the association between serum ferritin levels and neurodevelopment in infants. Data for this cross-sectional study were drawn from hospital information and early childhood development program service systems at Guangdong Women and Children's Hospital, Guangzhou, China. In total, 4579 infants aged 6-12 months were included from July 2018 to March 2020. Their neurodevelopment was assessed using the Children Neuropsychological and Behavior Scale-Revision 2016. Serum ferritin levels were measured by chemiluminescence assay. The association between serum ferritin levels and neurodevelopmental delay in each domain was estimated using logistic regression models adjusted for potential confounders. The mean concentration of serum ferritin was 35.56 ± 21.57 ng/mL. Serum ferritin levels were significantly higher in female than in male infants (P < 0.001). Iron deficiency (serum ferritin levels < 12 ng/mL) was significantly more prevalent in male than in female infants (P < 0.001). Linear regression revealed a positive association between serum ferritin levels and general quotient, gross motor, fine motor, language, and adaptive behavior in females. Iron deficiency was significantly associated with an increased risk of adaptive behavior delay in females (adjusted odds ratio (OR), 2.22; 95% confidence interval (CI): 1.17-4.20). Iron deficiency anemia was associated with an increased risk of developmental delay for general quotient (adjusted OR, 4.88; 95% CI: 1.74-13.65), fine motor (adjusted OR = 2.58, 95%: CI: 1.13-5.94) and adaptive behavior (adjusted OR, 3.38; 95% CI: 1.51-7.57) among females, but not in males. Associations between serum ferritin levels and neurodevelopment in infants aged 6-12 months were sex-related. Females with iron deficiency, especially those with iron-deficiency anemia, were more susceptible to neurodevelopmental delay than males.

Big data and reference intervals

Although reference intervals (RIs) play an important role in clinical diagnosis, there remain significant differences with respect to race, gender, age and geographic location. Accordingly, the Clinical Laboratory Standards Institute (CLSI) EP28-A3c has recommended that clinical laboratories establish RIs appropriate to their subject population. Unfortunately, the traditional and direct approach to establish RIs relies on the recruitment of a sufficient number of healthy individuals of various age groups, collection and testing of large numbers of specimens and accurate data interpretation. The advent of the big data era has, however, created a unique opportunity to "mine" laboratory information. Unfortunately, this indirect method lacks standardization, consensus support and CLSI guidance. In this review we provide a historical perspective, comprehensively assess data processing and statistical methods, and post-verification analysis to validate this big data approach in establishing laboratory specific RIs.

Iron Status in Relation to Low-Level Lead Exposure in a Large Population of Children Aged 0-5 Years

There are limited data regarding low lead exposure and iron status in Chinese children. This study aimed to examine the association between low-level lead exposure and iron status in a large population of children aged 0-5 years. We reviewed the records of children aged 0-5 years who had blood lead, iron, ferritin, and hemoglobin measurements during 2014-2017 at the Guangdong Women and Children Hospital. We identified 17,486 children with a blood lead level < 100 μg/L. Multiple linear and logistic regression analyses were performed to estimate the associations between blood lead levels and blood iron, serum ferritin, and hemoglobin. The mean concentrations of blood lead, iron, ferritin, and hemoglobin were 31.50 μg/L, 7.50 mmol/L, 46.98 ng/mL, and 120.41 g/L, respectively. Adjusting for age and sex, blood lead was negatively correlated with iron (r = - 0.073, p < 0.05), ferritin (r = - 0.043, p < 0.05), and hemoglobin (r = - 0.047, p < 0.05). Compared with the 1st quintile of lead exposure, the 5th quintile of lead exposure was associated with a 0.146 mmol/L decrease in blood iron, a 4.678 ng/mL decrease in serum ferritin, and a 1.245 g/L decrease in hemoglobin. Adjusted odds ratios (95% confidence interval) for the 5th quintile of blood lead were 1.39 (1.25-1.55) for iron deficiency and 1.45 (1.26-1.67) for anemia, relative to the 1st quintile. Our study findings confirmed the previously established association of blood lead levels with decreasing iron status and extended previous findings to even low-level lead exposure in Chinese children.

Functional reference limits: a case study of serum ferritin

Reference intervals depend on the distribution of results within a reference population and can be influenced by subclinical disease. Functional reference limits present an opportunity to derive clinically relevant reference limits from routinely collected data sources, which consist of mixed populations of unhealthy and healthy groups. Serum ferritin is a good example of the utility of functional reference limits. Several studies have identified clinically relevant reference limits through examining the relationship between serum ferritin and erythrocyte parameters. These ferritin functional limits often represent the inflection point at which erythrocyte parameters change significantly. Comparison of ferritin functional reference limits with those based on population distributional reference limits reveals that the lower reference limit may fall below the point at which patients become clinically unwell. Functional reference limits may be considered for any biomarker that exhibits a correlated relationship with other biomarkers.

Reference intervals established using indirect method for serum ferritin assayed on Abbott Architect i2000SR analyzer in Chinese adults

BACKGROUND

Serum ferritin (SF) test has been widely used in clinical practice. However, its reference intervals (RIs) vary depending on the analytical method and ethnic origin. This study was to establish the RIs using indirect method for SF in Chinese adults.

METHODS

SF was assayed on Abbott i2000SR analyzer. The SF test results of all health examinees (8913 males aged 18-93 years and 5397 females aged 18-90 years) between December 2010 and April 2019 were obtained from our laboratory information system. After Box-Cox transformation of raw data and exclusion of outliers, parametric and non-parametric approaches were used to calculate 95% RIs. The correlation between SF levels and ages, and the differences in SF levels between subgroups were also analyzed.

RESULTS

SF levels in females were significantly different from those in males (Z = 88.96, Z* = 23.17; Z > Z*) and showed a weak positive correlation with age (r = .466, P < .0001). The RIs based on parametric approach in males were 66.12-561.58 µg/L, whereas in all females were 3.59-269.59 µg/L, females aged <50 years 3.26-148.02 µg/L and those aged ≥50 years 17.28-303.27 µg/L. The RIs based on non-parametric approach in males were 65.00-571.37 µg/L whereas in all females were 4.00-254.00 µg/L, females aged <50 years 4.00-152.00 µg/L and those aged ≥50 years 16.00-304.05 µg/L.

CONCLUSIONS

Our indirect RIs for SF were markedly different from the manufacturer's recommended RIs and might be more suitable for Chinese adults, which would be helpful in interpreting laboratory data and clinical decision-making.