Blood biochemistry parameters

Role and status of the test in clinical practice

General medical blood biochemistry serves as a fundamental tool in the daily work of a clinician. According to current regulatory documents and clinical guidelines, the prescription of this test has a recommendation level of C, which corresponds to the fourth level of evidence. This means that performing this analysis is an established, reliable, and universally applied medical practice.

The most important organizational aspect in working with patients is proper routing. If the performed laboratory diagnostics reveal any deviations from established values, the patient is mandatorily referred for a consultation with a general practitioner. It is the general practitioner who provides the initial competent interpretation of the obtained data, correlates them with the clinical picture, and determines further patient management tactics.

In addition, regular biochemical monitoring is an absolutely integral part of any therapeutic process. This test is performed without exception for all patients both before initiating specific therapy (to assess the baseline background) and dynamically during its course. This allows the physician to timely track the reaction of body systems to the ongoing treatment.

Mandatory parameters of the basic analysis

The standard profile of general medical biochemical testing includes a strictly defined list of parameters, each of which is responsible for its own area. The mandatory diagnostic minimum includes the following parameters:

• Total protein — a baseline marker of protein metabolism in the body.
• Glucose — the most important and primary indicator of carbohydrate metabolism.
• Urea and creatinine — two key indicators reflecting the excretory function of the kidneys.
• Total bilirubin and conjugated bilirubin — markers of pigment metabolism that allow assessing the state of the hepatobiliary system.
• Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) — intracellular enzymes whose elevation in the blood reliably reflects cytolysis syndrome (cell destruction).

As part of special laboratory diagnostics, clinicians pay special attention to the assessed parameters: urea, creatinine, and total protein levels.

Profile expansion in specific conditions

Depending on the specific clinical situation, the basic list of biochemical parameters can and should be supplemented.

For example, when exercising strict biochemical monitoring during ongoing therapy, the mandatory panel, in addition to standard total protein, urea, creatinine, and total bilirubin, additionally includes:

• Albumin — the main transport fraction of blood plasma proteins.
• Vital electrolytes: potassium and sodium.

A completely special, expanded protocol is provided when a malignant renal neoplasm is suspected. In this case, all patients are strongly recommended to undergo both a complete blood count (with mandatory assessment of total hemoglobin, leukocyte, neutrophil, platelet counts, and erythrocyte sedimentation rate — ESR) and general medical biochemistry.

The biochemical profile in suspected renal tumor is strictly regulated. It mandatorily includes:

1. Creatinine.
2. Urea.
3. Total protein.
4. Albumin.
5. Total bilirubin.
6. Potassium.
7. Total calcium.

Differential diagnosis of laboratory methods

When ordering laboratory tests, it is extremely important for a student and a young physician to clearly distinguish between biochemical analysis and other types of laboratory diagnostics. In real clinical practice, general medical biochemistry should under no circumstances be confused with other tests that often appear in orders:

• Complete blood count (it assesses exclusively cellular composition and hemoglobin).
• Coagulogram (this is a specialized test of the hemostasis and clotting system).
• Ferritin blood test (this is a specific marker reflecting tissue iron stores).
• Urinalysis.
• Isolated determination of uric acid levels.

Each of the listed tests has its own strict indications for prescription and under no circumstances replaces a full general medical biochemical profile.

Class and exam questions

What else to study on this topic

• Complete blood count (CBC): hemoglobin, leukocytes, neutrophils, platelets, and ESR.
• Coagulogram as an independent method for assessing the blood coagulation system.
• Ferritin blood test: indications and clinical significance.
• The role of urinalysis in comprehensive laboratory diagnostics.
• Uric acid: the place of the parameter in biochemical monitoring.

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.