Lactate Dehydrogenase Isoenzymes
(LDH Isoenzymes)

Sample type

Serum (Red-top tube or gel-barrier tube)

Uses

An LDH isoenzymes test is used to find out the location, type, and severity of tissue damage. It can help diagnose a number of different conditions including:

Recent heart attack
Anemia
Kidney disease
Liver disease, including hepatitis and cirrhosis
Pulmonary embolism, a life-threatening blood clot in the lungs

Precautions

You don’t need any special preparations for an LDH isoenzymes test.

Interfering factors

A hemolyzed specimen is not acceptable as RBCs contain much more LD than serum.Causes can include transportation via pneumatic tube, vigorous mixing, or traumatic venipuncture. Tubes should be void of air bubbles to prevent minor hemolysis.
LD activity is one of the most sensitive indicators of in vitro hemolysis.
Hemolysis causes anomalous elevation of LD-1 such that any ex vivo hemolysis must be strictly avoided.
Freezing or prolonged storage at 4°C (>12 hours) causes LD-5 to be lost.
Elevations of intermediate forms (LD-2–LD-4) of LD are rarely used to define a tissue of origin, and such reports are largely anecdotal.
Although increases in serum LD also are seen following an MI, the test has been replaced by the determination of troponins.

Pre-analytical errors

Hemolysid samples
prolonged contact of serum with red cells
frozen specimen
specimen refrigerated more than three days after collection at time of testing

The corrective action

The sample must be rejected and another sample obtained.

Post-analytical errors

1-reports sent to the wrong patient

2- -write the wrong name in the report or the wrong results.

The corrective action

1-communication with patient, apologising for the error, and providing him with the correct report

2-If the report is not delivered to the patient and this error is discovered, The correct result must be written, but if the report is delivered to the patient, At this point, you must communicate with the patient and apologise to him, telling him that an error has occurred and giving him the correct report.

Reference range

LD ISOENZYMES

I (fast band): 17.5-28.3%

II: 30.4-36.4%

III: 19.2-24.8%

IV: 9.6-15.6%

V (slow band): 5.5-12.7%