As an essential auxiliary examination technique in modern clinical medicine, biochemical testing can directly reflect human organ function, substance metabolism and internal environmental homeostasis. It runs through the whole process of disease diagnosis, treatment formulation, condition monitoring and prognosis assessment [[1]]. Each clinical department mainly treats patients with specific systemic diseases, which lead to distinct target organ damage and metabolic disorders, and further result in characteristic changes of various biochemical indicators [[2]].

Diseases in the Department of Endocrinology and Nephrology are predominantly characterized by disorders of glucose and lipid metabolism as well as renal impairment, accompanied by abnormal levels of blood glucose, blood lipids and renal function indicators [[3]]. Cerebrovascular and neurological diseases in neurology departments may cause secondary changes in myocardial enzymes, electrolytes and liver function indicators [[4]]. The core manifestations of gastroenterological diseases include gastrointestinal mucosal injury and hepatobiliary dysfunction, which are often accompanied by remarkable abnormalities of bilirubin, transaminases and digestive enzymes [[5]]. At present, most clinical studies focus on biochemical indicators of a single disease or a single department. Horizontal comparative studies covering multiple departments and systemic diseases are still insufficient, making it difficult to establish a unified framework for the interpretation of biochemical results [[6]].

Based on the biochemical data of 373 inpatients from four key departments in our hospital, we summarized the main disease categories of each department and conducted a horizontal comparative analysis on the spectral characteristics of biochemical markers. The characteristic variations of biochemical indicators for different systemic diseases were clarified. The findings can assist clinicians in accurately interpreting laboratory reports, optimizing auxiliary diagnostic schemes, and provide basic data for the revision of hospital reference ranges and the establishment of disease screening systems.

This horizontal comparative study analyzed biochemical data of 373 inpatients from four departments, and verified that the biochemical profiles varied greatly among different departments. The changes of indicators were closely correlated with the pathological characteristics of corresponding diseases, which was consistent with previous domestic studies [[7]]. This study only reveals inter-department associations rather than independent diagnostic value, and the conclusions cannot be widely generalized to other medical institutions.

Patients in the Department of Endocrinology and Nephrology were mainly diagnosed with type 2 diabetes and chronic kidney disease. Defects in insulin secretion or action lead to elevated blood glucose. Long-term hyperglycemia can damage renal glomeruli, reduce glomerular filtration rate and cause accumulation of urea and creatinine in blood [[8]]. In addition, decreased protein synthesis and increased urinary protein loss in chronic kidney disease result in lower levels of ALB and CHE compared with neurological patients [[9]].

The Gastroenterology Department mainly admitted patients with gastrointestinal bleeding, hepatobiliary diseases and pancreatic diseases. Hepatocellular injury and biliary obstruction are the dominant pathological changes in gastroenterological diseases. ALT and AST are mainly located in hepatocytes; massive release of these enzymes into blood occurs when liver cells are damaged. Biliary excretion disorder causes elevated bilirubin and γ-GT, which are typical manifestations of hepatobiliary lesions [[10]]. The results of this study were fully consistent with the above pathophysiological mechanisms.

The neurology wards mainly treated patients with cerebrovascular diseases and peripheral neuropathy. Such diseases rarely cause liver synthetic dysfunction. Therefore, ALB and CHE remained at relatively high levels in neurological patients [[11]].

No significant differences were found in TG, CHOL, HDL and LDL among the four groups, which was inconsistent with some previous studies [[12]]. Glucose levels showed obvious inter-group differences. Most enrolled patients had chronic underlying diseases and received standardized lipid-lowering and hypoglycemic treatments during hospitalization. Meanwhile, blood lipid levels are affected by diet, lifestyle and medications, with individual differences outweighing inter-departmental differences.

In clinical practice, biochemical results should not be interpreted merely according to general reference ranges. Clinicians need to combine patients’ departments and specific diseases for comprehensive evaluation. For patients with endocrine and renal diseases, slight increases in blood glucose and renal indicators should arouse vigilance for diabetic nephropathy. Elevated transaminases and bilirubin in gastroenterology patients are mostly attributed to primary hepatobiliary diseases. Decreased ALB and CHE in neurological patients suggest potential combined hepatorenal damage.

There were significant differences in multiple biochemical indicators among inpatients from the four departments. GLU, Urea and CREA are characteristic markers for endocrine and renal diseases; bilirubin, transaminases and γ-GT are core indicators for gastroenterological disorders; ALB and CHE can be used to distinguish neurological patients from others. As a single-center retrospective study, the conclusions are only applicable to the local population and have limited diagnostic value for general use. Combined with patients’ departmental attribution and disease conditions to interpret biochemical results individually can maximize the clinical value of biochemical tests and improve the accuracy of clinical diagnosis and treatment.

First, this is a single-center retrospective study, so the conclusions have limited generalizability to other medical institutions. Second, this study only conducted overall inter-group comparison, without stratified analysis by age, gender, disease severity and treatment regimens, so the biochemical characteristics of different subgroups could not be clarified. Third, confounding factors such as medication history and underlying diseases could not be completely excluded in a retrospective design. In this study, normality test, homogeneity of variance test and post-hoc comparisons with multiple testing adjustment were completed; only admission baseline test data were used and repeated admission cases were excluded. Further multicenter, large-sample prospective studies with stratified analysis will be carried out to supplement and optimize the research results.

We sincerely thank all staff in the Department of Clinical Laboratory and clinical departments of Yizhou District People’s Hospital for their support and assistance in this research.

*Co-first author.

^#Corresponding author.