Mandatory biochemical blood test as a diagnostic standard
In routine clinical practice, medical specialists follow a strictly regulated list of mandatory biochemical blood tests. This panel is ordered for patients completely regardless of the current monitoring regimen, department specifics, or preliminary diagnosis. This fundamental diagnostic list invariably includes determining the activity of two key enzymes: alanine aminotransferase (ALT) and aspartate aminotransferase (AST).
However, these indicators are never evaluated in isolation. To ensure the attending physician receives the most complete and objective picture of the patient's internal organ status, the mandatory minimum biochemical test also includes the following critical parameters:
- Evaluation of serum glucose levels.
- Determination of total bilirubin concentration.
- Measurement of excretory function markers: urea and creatinine.
- Analysis of lactate dehydrogenase (LDH) activity.
Additionally, depending on specific clinical tasks, this baseline list may be expanded. Alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) activity testing are often considered as additional parameters.
Specifics of ordering AST and ALT in cytomegalovirus infection (CMV)
Special, close attention is paid to AST and ALT levels in the diagnostic and subsequent management protocols for patients with suspected cytomegalovirus infection (CMV).
When a clinician has a well-founded suspicion of a manifest form of CMV, the patient is ordered a specialized, expanded panel of laboratory tests. This panel invariably includes a general urinalysis as well as an extensive biochemical general therapeutic blood test. In this clinical scenario, the parameters required for quantitative evaluation are:
- Enzymes: ALT and AST.
- Additional enzyme markers: gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and alpha-amylase.
- Pigment metabolism indicators: not only total bilirubin, but also its individual fractions—free and conjugated bilirubin.
- Nitrogen metabolism indicators: urea and creatinine.
In addition to the biochemical profile, when a manifest form of CMV is suspected, it is critically important to perform a preliminary assessment of the hemostasis system. To this end, a coagulogram is ordered or precise determination of prothrombin (thromboplastin) time in the patient's blood or plasma is performed.
If the manifest form of CMV is already laboratory- and clinically confirmed, the diagnostic focus shifts somewhat. The general (clinical) blood count comes to the forefront, in which a differential leukocyte count (a detailed leukocyte formula is compiled) is invariably performed and platelet levels are carefully examined.
The role of AST and ALT in laboratory monitoring and general therapeutic profile
During continuous dynamic monitoring of patient status, the attending physician requires regular and accurate laboratory control. This monitoring is traditionally based on two main diagnostic tools: a clinical blood count and a biochemical test. As part of standard biochemical monitoring, ALT and AST levels, as well as total bilirubin, creatinine, and urea concentrations, are invariably monitored.
If it is necessary to perform the most complete biochemical general therapeutic blood test, an even more detailed and comprehensive profile is formed. The mandatory parameters of this advanced investigation include the evaluation of several body systems at once:
- Protein metabolism indicators: measurement of total protein and albumin concentration.
- Enzyme profile: determination of AST, ALT, lactate dehydrogenase (LDH), and alkaline phosphatase activity.
- Pigment metabolism evaluation: measurement of total bilirubin levels.
- Nitrogen metabolism markers: quantitative determination of urea and creatinine (uric acid is also added to some test panels).
- Electrolyte balance: mandatory measurement of total serum calcium and potassium levels.
ALT and AST are never evaluated alone in biochemistry: in any baseline test, they are always accompanied by Bilirubin, Urea, and Creatinine (the BUC rule).
Class and exam questions
Are AST and ALT included in the mandatory list of biochemical tests?
Yes, regardless of the patient's current monitoring regimen, the determination of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity is a strictly mandatory component of the baseline biochemical blood test.
What other enzymes are tested along with AST and ALT when manifest CMV is suspected?
When a manifest form of cytomegalovirus infection is suspected, in addition to AST and ALT, the levels of gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and alpha-amylase are invariably evaluated.
Which nitrogen metabolism indicators always accompany the AST and ALT test?
In any of the listed profiles (baseline screening, general therapeutic analysis, CMV monitoring), urea and creatinine levels are always measured alongside AST and ALT.
What else to study on this topic
- Differential laboratory diagnostics of manifest CMV infection.
- The role of bilirubin fractions (free and conjugated) in the expanded biochemical analysis.
- Evaluation of the coagulogram and prothrombin time in viral infections.
- The significance of electrolytes (potassium and calcium) in the general therapeutic blood profile.
- Changes in the leukocyte formula and platelet count in confirmed CMV infection.
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