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Liver

ALT in women: the upper limit of 34 U/l and what a rise means

Alanine aminotransferase, ALT for short, is an enzyme that according to the NVKC helps cells convert one substance into another. According to the NVKC, ALT is found mainly in the liver, with smaller amounts in the kidneys, the heart and the muscles.

If liver cells become damaged, ALT reaches the blood according to the NVKC, and according to Thuisarts a raised ALT can fit a fatty liver, medicines that can damage the liver, alcohol or gallstones, among other things. A blood test is the only way to see how high ALT is.

Certe gives an ALT below 34 U/L for women from age 18 and below 25 U/L for girls aged 13 to 18 as the reference values.

Doctor's Assessment Included

ALT is an enzyme, a protein that helps cells convert one substance into another; it is found mainly in the liver and enters the blood when liver cells are damaged. The four laboratories use an adult upper limit of 45 U/l for men and 34 U/l for women.

  • According to the NVKC, a slightly raised ALT without symptoms is not given a meaning straight away; only when the value is more than twice the upper limit is a search for the cause advised.
  • A normal or slightly raised ALT does not rule out serious liver disease such as cirrhosis, which is why ALT is often combined with other liver tests.
  • According to Thuisarts, when ALT is only slightly high, there is no clear cause and the person is not really ill, the GP can wait a few weeks and then test the blood again.

Reference Ranges

See the value that applies to you:

Choose male or female — this range differs by sex.

Enter your age — this range changes with age.

This range also depends on context such as cycle phase or sample material; the highlighted rows apply to your group.

Your reference range
u/l
8 52 u/l
Reference ranges by group, in u/l
Female · 1–5 years 10–33 u/l
10 33
Female · 6–12 years 9–33 u/l
9 33
Female · 13–18 years 8–35 u/l
8 35
Female · 19–50 years 9–44 u/l
9 44
Female · 51–65 years 11–52 u/l
11 52
Female · 66–80 years 10–46 u/l
10 46
Female · 81 years and older 8–37 u/l
8 37
8 52 u/l

Source: NVKC Reference population: Dutch general-practice population (NUMBER, n = 7,574,327)

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

Check your own value

ALT (Alanine Aminotransferase): what Dutch laboratories use

Reference ranges by group, in u/l
Star-shl · Female 0–34 U/l
0 34
Unilabs · Female · 19 years and older 0–34 U/l
0 34
Certe · Female · 18 years and older · a limit, not a range < 34 U/L
34
Diagnostiek voor U · Female · a limit, not a range < 34 U/L
34
0 37.4 u/l

Source: Star-shl

Source: Unilabs

Source: Certe

Source: Diagnostiek voor U

Each value as the laboratory itself publishes it, retrieved in 2026.

ALT (Alanine Aminotransferase): what this test measures

The ALT test measures the activity of the enzyme ALT in the blood in U/l, and the reference values differ by sex: all four laboratories give an upper limit of 34 U/l for adult women and 45 U/l for adult men.

ALT (Alanine Aminotransferase): why this value matters

Because the ALT upper limit at all four laboratories is 34 U/l for adult women and 45 U/l for adult men, the same ALT result can lie above the limit in a woman and below it in a man. The NVKC gives an ALT below 35 U/l for women without liver disease.

ALT (Alanine Aminotransferase): how the blood test works

Referral
No GP referral needed. After the order we arrange the referral through ZorgDomein, within one business day; orders after 17:00 or at the weekend start on the next business day. ZorgDomein emails a barcode, and that barcode is what the draw site needs.
The draw
A blood draw from a vein in the arm, at a partner laboratory's draw site. No home kit, no finger prick.
Which test
Complete Metabolic Panel · €149,-
Where
650+ draw sites run by independent laboratories across the Netherlands. Draw sites

ALT (Alanine Aminotransferase): how to prepare

  1. Better no hard training beforehand

    Recommended

    Hard exercise in the 48 hours before can raise this value temporarily. Plan the draw on a rest day if you can.

  • Water is always fine. Drink as usual beforehand, it makes the draw easier.
  • Take your usual medication, unless your own doctor told you otherwise.

ALT (Alanine Aminotransferase): when is testing worthwhile?

According to the NVKC, an ALT test is requested in people who have to take medicines that may damage liver cells, in people with liver disease in the family and in people who may have been infected with hepatitis B or C.

ALT (Alanine Aminotransferase): symptoms of a high or low value

Low Levels

For women, a low ALT is normal at all four laboratories: Star-SHL and Unilabs give 0 U/l as the lower limit, and Certe and Diagnostiek voor U give only an upper limit. Loss of muscle mass goes together with a low ALT in the general population, according to a 2023 research article in European Urology Open Science.

High Levels

Medicines that can damage the liver, including ones bought in a shop, are a possible reason for a raised ALT according to Thuisarts, as are gallstones or another disease of the liver, the gall bladder or the pancreas. According to the NVKC, in chronic hepatitis ALT is raised up to a maximum of 5 times the normal value, less strongly than in acute hepatitis.

ALT (Alanine Aminotransferase): causes of a low or high value

What lowers the value

  • Low muscle mass

    In studies of the general population, a low ALT goes together with loss of muscle mass.

  • Vitamin B6 deficiency

    Vitamin B6 is needed to make ALT; a deficiency, which is common with long-term heavy drinking, reduces how much ALT is made.

What raises the value

  • Fatty liver

    A fatty liver, too much fat in the liver, can raise ALT and the other liver tests in the blood.

  • Alcohol

    Drinking alcohol is one of the causes of a raised ALT and other raised liver tests.

  • Medicines and drugs

    Medicines that can damage the liver, including ones bought without a prescription, and drugs such as cocaine or ecstasy can raise ALT and the other liver tests.

  • Acute viral hepatitis

    An ALT more than 15 times the upper limit is almost always caused by acute hepatitis, which is usually caused by a virus.

  • Heavy weight training

    In one study, ALT stayed raised for at least 7 days after an hour of heavy weight training in healthy men who were not used to it.

ALT (Alanine Aminotransferase): lifestyle and this value

Talk to your GP about a raised ALT, and Thuisarts recommends also naming medicines, herbs or vitamins bought in a shop.

ALT (Alanine Aminotransferase): frequently asked questions

Is an ALT of 35 U/l too high in a woman?

In an adult woman, an ALT of 35 U/l lies just above the upper limit of 34 U/l used by Star-SHL, Unilabs, Certe and Diagnostiek voor U. According to the NVKC, ALT in women without liver disease is below 35 U/l, so a value of 35 U/l also falls just outside that. The NVKC says that no direct meaning is attached to such a slightly raised value without symptoms.

Can gallstones raise ALT?

According to Thuisarts, gallstones can be a reason that the liver tests, including ALT, are abnormal.

ALT (Alanine Aminotransferase): sources

  1. den Elzen WPJ, Brouwer N, Thelen MH, Le Cessie S, Haagen I-A, Cobbaert CM. NUMBER: standardized reference intervals in the Netherlands using a 'big data' approach. Clin Chem Lab Med 2018;57(1):42-56. (retrieved 2026) doi.org
  2. Star-shl, Labbepalingen (referentiewaarden per bepaling), star-shl.nl, geraadpleegd 2026-10-01 (retrieved 2026) star-shl.nl
  3. Unilabs, Bepalingenklapper (referentiewaarden per bepaling), bepalingenklapper.nl, geraadpleegd 2026-10-01 (retrieved 2026) bepalingenklapper.nl
  4. Certe, Bepalingenwijzer (referentiewaarden per bepaling), bepalingenwijzer.certe.nl, geraadpleegd 2026-10-01 (retrieved 2026) bepalingenwijzer.certe.nl
  5. Diagnostiek voor U, eLabgids (Referentiewaarden DvU), diagnostiek.getincontrol.eu, geraadpleegd 2026-10-01 (retrieved 2026) diagnostiek.getincontrol.eu
  6. Laufer M, et al. Low Alanine Aminotransferase, as a Marker of Sarcopenia and Frailty, Is Associated with Shorter Survival Among Prostate Cancer Patients and Survivors. Eur Urol Open Sci 2023. (retrieved 2026) pmc.ncbi.nlm.nih.gov
  7. Malakouti M, et al. Elevated Liver Enzymes in Asymptomatic Patients - What Should I Do? J Clin Transl Hepatol 2017;5(4):394-403. (retrieved 2026) pmc.ncbi.nlm.nih.gov
  8. NHG, Thuisarts.nl: De levertesten van mijn bloed zijn niet goed, geraadpleegd 2026-10-06 (retrieved 2026) thuisarts.nl
  9. NVKC, Alles over testen: ALAT, allesovertesten.nl, geraadpleegd 2026-10-06 (retrieved 2026) allesovertesten.nl
  10. Pettersson J, et al. Muscular exercise can cause highly pathological liver function tests in healthy men. Br J Clin Pharmacol 2008;65(2):253-259. (retrieved 2026) pmc.ncbi.nlm.nih.gov

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