Transaminases increase

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Classification according to ICD-10
R74.0 Increase in transaminase levels and lactate dehydrogenase (LDH) levels
ICD-10 online (WHO version 2019)

In medicine, one speaks of an increase in transaminases when the levels of aspartate aminotransferase (abbr. GOT, ASAT or AST) or alanine aminotransferase (abbr. GPT, ALAT or ALT) in the blood are increased as part of an enzyme diagnosis . The specific level of the measured values, the temporal course of the transaminase level and the relationship to one another, but also the comparison with other measurement parameters, are of diagnostic importance.

Basics

→ Main article transaminases

Transaminases (syn. Aminotransferases ) catalyze a common biochemical reaction in the intermediate metabolism of all living organisms . From this extensive group of enzymes, two play an important role in medical diagnostics , especially for the detection of heart or liver diseases. Both enzymes are found within the cells of numerous types of tissue either freely in the cytosol or bound to mitochondria . An increase in transaminases therefore indicates damage to the corresponding cells (only in this case is it possible for the enzymes to escape into the blood in relevant quantities) . The laboratory determination of the transaminases in the blood is carried out indirectly by means of photometric measurement of the enzyme activity (measurable metabolism per time interval). Therefore, the result of an analysis is not given in weight unit (enzyme) per volume unit (blood serum), but in “activity units” per volume unit blood serum (U / l). The German notation "units per liter" (E / l) can also be found in the current literature. The normal values ​​of the transaminases depend on the method, but are generally not more than 40 U / l for both. The transaminases are milk-permeable.

In the literature, terms used synonymously for GOT and GPT can be found, which, however, are used less often in clinical parlance:

  • GOT (glutamate oxaloacetate transaminase): S-GOT (serum glutamate oxaloacetate transferase), ASAT, AST ( aspartate aminotransferase )
  • GPT (glutamate pyruvate transaminase): S-GPT (serum glutamate pyruvate transferase), ALAT, ALT ( alanine aminotransferase )

meaning

Transaminases are found in particularly high concentrations in the liver (GOT and GPT) and heart (GOT only). Therefore, they play a major role in the diagnosis of diseases in both organs that are associated with cell damage. The GOT is also found in a diagnostically relevant amount in the striated muscles .

Liver diagnostics

In addition to GLDH and γ-GT, GOT and GPT are typical indicators of damage to the liver cells ; the extent of the increase correlates with the extent of the damage. Dissolved in the cytoplasm, GOT and GPT are found in the liver, only the GOT bound to mitochondria, so they are released to varying degrees in diseases. Their correlation (GOT / GPT) describes the De-Ritis quotient . In the case of slight liver cell damage it is less than 1, in the case of severe liver cell damage it is greater than 1. In the case of extensive liver cell necrosis (for example in the context of virus hepatitis ), the transaminases can rise to over 1000 U / l. A drop in laboratory values ​​in the further course of the disease can indicate both an improvement in the condition and the onset of liver failure due to extensive destruction of liver parenchyma cells.

Cardiac diagnostics

GPT does not occur to a relevant extent in the heart muscle. Therefore, in the case of cardiac muscle damage (e.g. heart attack ), only an increase in GOT can be expected. This increase can be detected between four hours and 3–6 days after the start of a heart attack. If there is also an increase in GPT after a heart attack, this indicates that the liver is involved (e.g. liver congestion as a result of right heart failure ) or another type of accompanying liver disease.

Muscle disorders

Since the 1950s, increases in GOT have also been known in diseases that directly affect the striated muscles , such as muscular dystrophy , myositis and myopathy . An increase in GOT is absent in neurogenic forms of muscle atrophy , which is why GOT is of differential diagnostic importance here. The GOT can also be increased in the case of trauma associated with damage to the muscle cells.

Further meaning

Temporary or long-term increases in transaminases can be seen with many drugs, including cephalosporins , flutamide, and gabapentin . Additional findings can also be found in clinical pictures such as HELLP syndrome .

Individual evidence

  1. ↑ Koolman J., et al .: TaschenAtlas der Biochemie , Thieme Verlag, 2002, p. 424, ISBN 3137594030 , here online
  2. ↑ Fallmann H .: Biochemie , Vieweg + Teubner Verlag, 2001, p. 104ff., ISBN 3519003333 , here online
  3. ↑ Hallbach J .: Clinical Chemistry for Beginners , Thieme Verlag, 2006, pp. 140ff., ISBN 3131063424 , online here
  4. ↑ a b Dubach UC, ea: Transaminase determinations in obstetrics . In: Archives of Gynecology and Obstetrics, Springer Verlag, 1958, 190/4, pp. 394-403, ISSN  0932-0067 , here online
  5. ↑ Herold G .: Internal Medicine , self-published, 2007, pp. 463–465.
  6. ↑ Major E .: Risks and Complications in Anesthesia , Urban & FischerVerlag, 1997, p. 122, ISBN 3437210580 , here online
  7. ↑ Herold G .: Internal Medicine , self-published, 2007, pp. 220–222.
  8. ↑ Kaeser HE: The behavior of the serum glutamic acid-oxaloacetic acid transaminase in myopathies and neurogenic muscle atrophies . In: Journal of Neurology, Steinkopff Verlag, 1959, 179/4, pp. 353-362, ISSN  0340-5354 , here online