What influences laboratory results?

What influences the laboratory results? What errors can occur and what do they result from? How do I properly prepare for the examination? All these questions I will try to answer with solid arguments;)

Laboratory diagnostics provide about 60% of the information needed to assess the patient’s health and correctly manage the patient’s treatment process. The results of laboratory tests are needed to diagnose the disease, to evaluate its course and to evaluate the efficacy of the treatment applied.

Laboratory tests are also carried out during dietary therapy to check the effectiveness of their effects. Therefore, when working with a nutritionist, you have to expect a specialist to do it.

Test material

Laboratory tests are most commonly performed with blood (venous, arterial or capillary) and urine. In special situations, faeces, liquor, fluid from body cavities, saliva and kidney and gallstones may also be used as material.

The arterial cream is mainly taken by doctors and is used to assess the gasometry and the acid-base balance of the blood. Capillary blood is taken from the heel in newborns and less frequently from the fingertips in adults to measure blood sugar.

The diagnostic material may be a so-called whole blood or a part of it after it has separated itself. If whole blood is needed, an anticoagulant is put into the tubes or bowls to prevent blood clotting. And for some of the blood, no anticoagulants are used.

Blood serum, i.e. plasma free of fibrinogen and the factors used for the formation of fibrinogen. The blood clot and the morphotic elements of the blood are separated from the whole blood.

Blood plasma is a fluid component of the blood in which the morphotic elements of the blood are suspended.

Whole blood is the material from which the peripheral blood count and the blood smear are evaluated.

Urine is the diagnostic material that is most sensitive to changes in the body. It detects most diseases and inflammations. My wife, Dr. from Poznań Medical University, used to quote in class: “Whether you lose weight or become fat, everything is discovered in your urine.”

Nothing to believe, nothing to add. He’s right. That is why urine is, in addition to blood, a subjective risk detector or a source of health information.

What influences laboratory results?

Appropriate preparation of the patient, appropriate conditions for the examination itself, conditions for the transport of materials and appropriately qualified diagnostic laboratory staff are required for the proper conduct of diagnostic examinations.

Now you know what a complicated process this is. Every mistake will lead to a domino effect of the next steps. Therefore, it is important to know how to prepare for the test to reduce the risk of false test results.

Biological variability plays an important role in the result of a laboratory test. Take into account: age, race, gender, diet, stimulants, physical activity and medicines taken.

Other study results will include children, adults of childbearing age and other elderly people. Differences in the results between men and women will be mainly apparent in the values of certain hormones and parameters during pregnancy.

What influences the results of laboratory tests – Diet

Nutrition is an important factor influencing a number of parameters. A protein-rich and high-urine diet leads to increased levels of ammonia, urea and uric acid in the serum. A low-protein diet, on the other hand, leads to a decrease in the concentration of prealbumin and the retinol-binding protein.

Many parameters are also changed during fasting: lowering of cholesterol, triglycerides and urea, increasing of creatinine and uric acid. In addition, the excretion of ammonia and creatinine in the urine is increased and the excretion of calcium and inorganic phosphates is reduced.

To avoid misinterpretation of laboratory values, it is recommended not to change the diet before fasting blood (approximately 12 hours after the last meal).

Alcohol consumption up to 2 days before testing even affects the following factors: a decrease in blood sugar, an increase in lactate, a decrease in bicarbonate, metabolic acidosis and an increase in serum uric acid.

Chronic alcohol consumption increases mean erythrocyte volume (MCV), increases glutamyltransferase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and triglycerides.

What influences laboratory results – other factors

Cigarette smoking also changes some parameters, such as increased white blood cell counts, MCV, mean red blood cell haemoglobin mass (MCH), cholesterol, fibrinogen and heavy metals (cadmium and lead).

Moderate physical activity affects glucose, cholesterol and triglyceride levels. Intensive physical exertion increases creatine kinase (CK), aspartate aminotransferase, albumin, uric acid, creatinine, leukocytes and platelets.

It is therefore recommended to be as physically active as possible one day before the examination and not to do any intensive exercises on the day of the examination.

Also factors such as time of day (due to cortisol or potassium levels), body position during the examination (not sitting may affect plasma proteins, cholesterol, red and white blood cell counts).

At the further stage of the diagnostic analysis, i.e. the method of blood collection, storage conditions and transport are also important, e.g. the use of an appropriate anticoagulant and

I hope to have given you a little insight into the correct conduct of diagnostic tests and the factors that influence the result. Now you are more informed about how to prepare for the study.

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