Preparing for blood donation

Blood sampling for most tests is done on an empty stomach (when there is at least 8 hours between the last meal and the taking of blood). For example, biochemical test of glucose, cholesterol, bilirubin must be taken on an empty stomach; serological analysis of syphilis, viral hepatitis, hormones (TSH, parathyroid hormone, etc.). You can drink water, but a little.

Between the last meal and the blood donation for a general analysis should take at least 1 hour.

Before donating blood to determine the lipid profile: cholesterol, HDL, LDL, triglycerides, etc. should refrain from eating for at least 8 hours.

The results of hormonal studies in women of reproductive age (from about 12–13 years before menopause) are influenced by factors associated with the phase of the menstrual cycle, therefore, in preparation for the analysis of hormones (FSH, LH, prolactin, estradiol, progesterone), the phase of the cycle should be indicated.

Thus, when testing for sex hormones, it is necessary to strictly adhere to the instructions of the attending physician regarding which will mark the most optimal days for donating blood days of the cycle.

When performing tests for infections, it should be borne in mind that, depending on the period of the infection process and the state of the immune system, the result of the study may be false negative, i.e. analysis does not always confidently exclude infection.

In doubtful cases, re-analysis.