ENZYMOLOGY 1 LDH "LACTATE DEHYDROGENASE"

What is the activator of Lactate Dehydrogenase

ZINC

Lactate dehydrogenase catalyzes the interconversion of....

lactic acid and pyruvic acid

LDH is composed of how many isoenzyme sub unit?

4

Other term for LDH-6, it is also known as the 7th isoenzymes

ALCOHOL DEHYDROGENASE ENZYME

The 6th LDH isoenzyme

LD-X or LDHc

Isoenzymes of LDH that should be analyzed within 24 hours

LDH 4 and 5 (THEY ARE COLD LABILE)

when LDH-5 is elevated what isoenzymes is automatically present?

LDH-6 or ALCOHOL DEHYDROGENASE

What isoenzyme has the highest concentration

LDH-2

Total LDH is normally increased (temporarily) during ______________ and returns after 24hours

BLOOD TRANSFUSION

LDH is elevated in?

Pernicious anemia and hemolytic disorder

LDH is 10 fold increase in

hepatic carcinoma and toxic hepatitis

Normal pattern of isoenzyme serum concentration

2-1-3-4-5

What is a "flipped pattern"?

when LDH-1 is higher than LDH-2

What indicates flipped pattern

ACUTE MYOCARDIAL INFACTION

The peak time of AMI

48-72 hours

The rise time of AMI

24-48 hours

How many days of does AMI serum is elevated

10-14 days

Ratio for LDH-2:LDH-1

less than 0.75 and often exceeds 1.0

LDH-5 (cold labile) is markedly increased during

hepatic carcinoma and toxic hepatitis

LDH-5 (cold labile) is moderately increased during

acute viral hepatitis and cirrhosis

LDH-6 is ELEVATED during

DRUG HAPATOXICITY AND OBSTRUCTIVE JAUNDICE

LDH-6 during

ARTERIOSCLEROTIC FAILURE AND IMPENDING DEATH

Serum LDH sample is can be stored at room temp for how long?

2-3 days without changes

recommended sample for LDH and can w accept hemolyzed sample?

- SERUM is recommended,
- NO to hemolyis it increases the RBC concentration

LDH reference values

- 125-220 U/L (37degrees C)
- 100-225 (forward)
- 80-280 (reverse)

Forward reaction (lactate to pyruvate)

8.3 to 8.9

Reverse reaction (pyruvate to lactate)

7.1 to 7.4