Checkup Liver Numbers: AST Splits at 40 and ALT at 35, Gamma-GTP Differs for Men and Women, and Borderline and Suspected-Disease Ranges Are Separate
On a health checkup report, the liver section shows three lines side by side, AST, ALT and gamma-GTP (γ-GTP), and the judgment letters next to them are often different. AST may be normal while gamma-GTP alone is marked "borderline," and the same number can be normal for a man and "suspected disease" for a woman. This post follows the judgment criteria in Annex 4 of the Health Examination Implementation Standards (a Ministry of Health and Welfare notice) and the Korea Disease Control and Prevention Agency's health information, and sets out where each of the three values changes category and what to check after you receive the result.
The three liver values are judged separately
The liver items in the general health examination are AST (SGOT), ALT (SGPT) and gamma-GTP, all measured in U/L. Each one gets its own judgment, so a single line alone cannot tell you "my liver is fine" or "my liver is bad." The notice defines the categories this way. Normal A means health is good. Normal B (borderline) means nothing is wrong yet, but self-management and preventive steps such as diet and lifestyle changes are needed. Suspected disease means there is a chance of developing a disease and follow-up tests or an exact diagnosis at a medical institution are needed. The full five-level structure is covered separately in the judgment categories on a checkup report.
AST and ALT have different borderline lines
In the item-by-item criteria, AST is 40 or below for Normal A, 41 to 50 for Normal B (borderline), and 51 or above for suspected disease. ALT is 35 or below for Normal A, 36 to 45 for Normal B (borderline), and 46 or above for suspected disease. Because the two lines sit five apart, an AST of 48 is borderline, while an ALT of 48 is already suspected disease. The same number is judged differently depending on the item. The "reference range" printed on a hospital report can differ slightly between laboratories, but the judgment categories of the national checkup follow the notice.
Gamma-GTP differs for men and women
Gamma-GTP is split by sex. For men, 11 to 63 is Normal A, 64 to 77 is Normal B (borderline), and 78 or above is suspected disease. For women, 8 to 35 is Normal A, 36 to 45 is Normal B (borderline), and 46 or above is suspected disease. A value of 50 is Normal A for a man but suspected disease for a woman. This is why a number found online can read the wrong way round if you compare it without checking sex. Look at the line for your own sex first.
A high AST does not automatically mean a liver problem
According to KDCA health information, AST is an enzyme found not only in the liver but in most tissues of the body, including the heart, muscle and blood cells. So when AST is high but ALT is within range, factors other than the liver need to be considered too. ALT is generally described as being concentrated more in liver cells, which is why the two values are read together. Whether you exercised hard the day before the checkup or had muscle injury is worth telling the doctor who reads your result.
Common things that raise the values
In the examples KDCA gives, gamma-GTP can rise with alcohol, obesity, acetaminophen, anticonvulsants and oral contraceptives, and AST and ALT are also affected by drinking, some medicines and liver cell damage. The important point is that the number alone does not reveal the cause. The same value could come from drinking, from a medicine you take, or be related to weight. We do not recommend guessing at a cause from one report and stopping or switching medicines or supplements on your own. Talk to the doctor or pharmacist who prescribed what you take.
When the result is borderline and when it is suspected disease
As defined in the notice, Normal B (borderline) is the stage where self-management and preventive steps are needed. Check the lifestyle guidance you received at the checkup and compare whether things moved in the same direction by your next checkup. Suspected disease is described as the stage that needs follow-up tests or an exact diagnosis at a medical institution. If the result notice shows a suspected-disease item, book a consultation with an internal medicine clinic nearby and bring the report, a list of the medicines you take and how much you usually drink. If other items such as cholesterol were flagged too, see also the cholesterol retest criteria.
Reading it alongside the other items
The liver items do not stand alone on a checkup sheet. When waist size, body mass index, fasting glucose and triglycerides are also in the borderline range, gamma-GTP is often elevated alongside them, but that too is a whole-picture judgment for a doctor rather than something to read item by item. For a test whose judgment works differently, such as bone health, see the bone density T-score criteria. You do not need to memorize every item's thresholds each time you open your results. It is more useful to download the last ten years of your checkup results from the National Health Insurance Service "Health iN" site and look at how the numbers have moved.
Order of steps when you receive the report
First, read the judgments for AST, ALT and gamma-GTP item by item. Second, check that gamma-GTP was judged on the criteria for your sex. Third, if borderline, review the lifestyle guidance; if suspected disease, arrange a medical consultation. Fourth, note the medicines you take, recent drinking and any exercise before the checkup. This post does not replace diagnosis or treatment, and what a value means depends on the individual situation, so ask a doctor for a specific interpretation.
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