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P -Hcyst

All cells of the body contain low amounts of an amino acid that contains sulphur, homocysteine (Hcyst). Homocysteine is produced through another essential amino acid that we obtain from food.

Usually, the body processes homocysteine quickly using folate, and the values remain low. Folate is one of the B vitamins, vitamin B9. Vitamin B12, on the other hand, is needed for keeping folate in the active form.

When should homocysteine be measured?

Homocysteine can be measured in connection with the following symptoms:

  • Anaemia
  • Muscle weakness
  • Memory disorders
  • Sensory disorders (stinging in the arms and legs)
  • Changes in the oral mucosa
  • Skin changes
  • Weakened immune defence
  • Slowing down of growth
What does a homocysteine test measure?

Homocysteine levels can increase with folate, vitamin B6, or vitamin B12 deficiency. Folate is found in liver, green leafy vegetables, and grains, among other sources. Vitamin B12 is found in red meat, fish, poultry, and seafood.

A homocysteine test is done if suspecting vitamin B12 and B6 or folate deficiency.

Elevated homocysteine levels have been suspected of being linked to cardiovascular risks, but the evidence has been contradictory so far.

Normally, the result is: 

Reference values:

  • 5.0–15.0 µmol/l

Please contact your physician or other healthcare professional if you suspect an illness or need help interpreting the results.

Read more about defining reference values.

Elevated homocysteine levels can be hereditary or acquired. Furthermore, homocysteine levels can increase with age, especially in women after menopause. High homocysteine levels can be caused by:

  • Vitamin B12 or B6 and folic acid deficiency
  • Smoking
  • Alcohol
  • Certain drugs
  • Kidney failure
  • Hypothyroidism (underactive thyroid)

Homocystinuria is a rare inherited disorder of the metabolism that involves high homocysteine levels. Affected individuals appear normal at birth but develop serious complications in childhood.

  • Vitamin B6 affects the functioning of the nervous and immune systems (3429 S-B6-vit)
  • Vitamin B12 supports the function of the brain and nervous system (1142 S-B12-TC2)
  • Folic acid affects the well-being of the brain and cells (1416 fS-Folaat)

SYNLAB test list: Homocysteine, plasma (P-Hcyst) https://www2.synlab.fi/laboratoriokasikirja/tutkimuskuvaukset/homokysteiini-plasmasta-1867-p-hcyst/

LabTest online: Homocysteine https://labtestsonline.org.uk/tests/homocysteine

Duodecim: Homokysteiini ja sepelvaltimotauti https://www.duodecimlehti.fi/duo93626


Fasting is not required

This examination does not require fasting