BackgroundHomeostasis is a mechanism for maintaining a stable inner environment in healthy participants. Blood and urine biomarkers are indicators of the subject health status. Biomarkers apply for early diagnosis, prognosis, and treatment. Understanding the effect of pre-analytical factors on biomarker range is significant for the data quality of bio-specimens, reproducibility, and minimizing potential results errors. Water as a necessary element for the normal functioning of living beings and sampling frequency as pre-analytical factors influences the homeostatic range of parameters. The purpose of the study is to examine the effect of 9-day fluid intake and 2-time sampling on concentration changes of 7-urine (freezing point depression, potassium, sodium, chloride, urea, creatinine, urate) and 17-blood (urea, creatinine, urate, glucose, C-reactive protein, leukocytes, erythrocytes, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, mean platelet volume, thrombocytes, potassium, sodium, and chloride) variables.MethodsParametric and non-parametric test apply to data processing with SPSS software v23.0.ResultsThe group of 23 healthy subjects was divide based on water intake (test: more than 1800 ml; control: less than 2000 ml) and gender (female: 10(43%); male: 13(57%)). The mean value of the amount of fluid consumed for the test group is 2183.33 ml, while the control is 1395.83 ml. Investigated parameters, freezing point depression, sodium, potassium, creatinine urea and urate in urine, urea, urate, glucose, hematocrit, and thrombocyte in blood show a significant difference (P < 0.01) between the first and second sampling. The difference between water intake after first sampling (P < 0.01) observes for freezing point depression, sodium, urate, and (P < 0.05) for potassium (P < 0.05), chloride (P < 0.05), creatinine (P < 0.05), urate, urea in urine and potassium (P < 0.01), and chloride (P < 0.05) in blood. Difference between gender exists for urea (P < 0.05) in urine after second sampling and urate (P < 0.01), glucose (P < 0.01/0.05), hematocrit (P < 0.01/0.05) after the first and second sampling, and mean corpuscular hemoglobin concentration (P < 0.01) after secondary sampling in blood samples.ConclusionWater intake increases the blood and urine biomarker range after the first and second sampling. Further studies should include a larger number of participants to get precise reference limits in a healthy population. Compare health and disease states to draw practical clinical conclusions.