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Test ID: ALT
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Alanine Aminotransferase
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Useful For
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Diagnosis and monitoring of liver disease associated with hepatic necrosis.
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Method name and description
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This assay follows the recommendations of the IFCC, but was optimized for performance and stability. ALT catalyzes the reaction between L‑alanine and 2‑oxoglutarate. The pyruvate formed is reduced by NADH in a reaction catalyzed by lactate dehydrogenase (LDH) to form L‑lactate and NAD + .
ALT
L-Alanine + 2‑oxoglutarate pyruvate +  L‑glutamate
LDH
Pyruvate + NADH + H + L‑lactate + NAD +
The rate of the NADH oxidation is directly proportional to the catalytic ALT activity. It is determined by measuring the decrease in absorbance.
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Clinical information
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ALT has been widely reported to be present in a variety of tissues. The major source of ALT is the liver, which has led to the measurement of ALT activity for the diagnosis of hepatic diseases.
High ALT is found in Hepatitis, Cirrhosis, Obstructive jaundice, Carcinoma of the liver, chronic alcohol abuse, slightly elevated in patients who have an uncomplicated myocardial infarction. In patients with vitamin B6 deficiency, serum aminotransferase activity may be decreased.
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Specimen type / Specimen volume / Specimen container
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Specimen type: Serum, Plasma
Minimum volume of sample: 1 mL
Serum: Plain tube (red or yellow top, free from hemolysis)
Plasma: Li‑heparin (free form hemolysis)
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Collection instructions / Special Precautions / Timing of collection
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Storage and transport instructions
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Storage: 3 days at 15 – 25°C
7 days at 2 – 8°C;
> 7 days at ‑60 to -80 °C
Transport: 2-25°C
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Specimen Rejection Criteria
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Grossly hemolyzed, icteric and lipemic, wrong collection container, insufficient sample.
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Biological reference intervals and clinical decision values
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Age
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Reference Interval (U/L)
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From
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To
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From
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To
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Male
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0 minutes
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1 month
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1
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25
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Male
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1 month
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1 year
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4
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35
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Male
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1 year
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3years
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5
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30
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Male
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3 years
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6 years
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5
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20
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Male
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6 years
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9 years
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5
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25
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Male
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9 years
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18 years
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5
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30
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Male
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>18 year
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0
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41
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Female
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0 minutes
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1 month
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2
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25
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Female
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1 month
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1 year
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3
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30
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Female
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1 year
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3 years
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5
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30
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Female
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3 years
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9 years
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5
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25
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Female
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9 years
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18 years
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5
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20
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Female
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>18 year
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0
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33
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Factors affecting test performance and result interpretation
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Lipemic samples may cause > Abs flagging. Choose diluted sample treatment for automatic rerun.
Calcium dobesilate and Isoniazid can cause artificially low and Furosemide artificially high ALT results at therapeutic concentrations. Cyanokit (Hydroxocobalamin) may cause interference with results
Physiological plasma concentrations of Sulfasalazine or Sulfapyridine may lead to false results.
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Turnaround time / Days and times test performed / Specimen retention time
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Daily (24/7)
Turn-around time:
STAT: 1 hour
Routine: One working day
Specimen retention: 4 days
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