Lactate Dehydrogenase in Human Serum with Roche c502

Detection of Lactate Dehydrogenase in Human Serum with Roche c502

Test Name: In vitro test for the quantitative determination of lactate dehydrogenase in human serum and plasma on Roche/Hitachi cobas c systems.
Method Name: Lactate dehydrogenase catalyzes the conversion of L-lactate to pyruvate. NAD is reduced to NADH in the process. The initial rate of the NADH formation is deirectly proportional to the catalytic LDH activity. It is determined by photometrically measuring the increase in absorbance.
Results: Technical Range: 10-1000 U/L
Reportable Range: 10-863 U/L
Reference Ranges: 1-30 days: 135-750 U/L
31 days-11 months: 180-435 U/L
1-3 years: 160-370 U/L
4-6 years: 145-345 U/L
7-9 years: 143-290 U/L
10-12 years: 120-293 U/L
13-15 years: 110-283 U/L
16-17 years: 105-233 U/L
≥18 years: 122-222 U/L
  Clinical Significance:   The lactate dehydrogenase (LDH) enzyme is widely distributed in tissue, particularly in the heart, liver, muscles and kidneys. The LDH in serum can be separated into five different isoenzymes based on their electrophoretic mobility. Each isoenzyme is a tetramer composed of two different subunits. These two subunits have been designated heart and muscle, based on their polypeptide chains. There are two homotetramers, LDH 1 (heart) and LDH 5 (muscle), and three hybrid isoenzymes.

Elevated serum levels of LDH have been observed in a variety of disease states. The highest levels are seen in patients with megaloblastic anemia, disseminated carcinoma and shock. Moderate increases occur in muscular disorders, nephrotic syndrome and cirrhosis. Mild increases in LDH activity have been reported in cases of myocardial or pulmonary infarction, leukemia, hemolytic anemia and non-viral hepatitis.

Submission Criteria: For specimen collection and preparation, only use suitable tubes or collection containers. Only the specimens listed below were tested and found acceptable.
Plasma: Li-heparin

NOTE: Plasma from primary tubes handled according to the manufacturer’s instructions can still contain cells, leading to implausibly high results. One option for these cases is an application with automatic sample pre dilution (ACN 147/ACN 8147). Alternatively, it is recommended to transfer the plasma from the primary tube to a secondary sample tube.

The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, therefore not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases.  When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.

Storage and Stability:    42 days at (-15°C) – (-20°C)
4 days at 2-8°C
7 days at 20-25 °C

Note: In connection with certain diseases (e.g. hepatopathy, diseases of skeletal muscle, malignant tumors), the LDH-4 and LDH-5 isoenzyme portions are increased and unstable in cooled and frozen samples; this may lead to an incorrect LDH value in samples collected from patients suffering from such diseases.

Rejection Criteria: Rejection criteria include but are not limited to:
1. Specimens containing fibrin or clots.
2. Excessive platelet clumping
3. Leaking specimens
4. Substandard mixing or collection
5. Expired or improperly stored collection tubes.
6. Improperly filled tubes based on collection tube manufacturer’s guidelines.
7. Contaminated specimens (IV fluid, foreign particles, etc.)
8. Specimens not analyzed within the appropriate time frame.
9. Samples not shipped at appropriate temperature.
10. Samples without 2 proper identifiers or samples having identifiers that do not match the electronic or paper lab requisition.
Authorization: Diagnostic testing can only be performed with approval from an authorized provider/agency.
Turn Around Time: 1 day.