Leucine Amino Peptidase
(LAP)

Sample type

24-hour urine

Uses

1-As a marker of hepatic and pancreatic carcinoma.

2-As a marker of early tubular (renal) injury in diabetes and as an indicator of SLE activity.

3-Parallels serum ALP except that

• LAP is usually normal in the presence of bone disease or malabsorption syndrome.

• LAP is a more sensitive indicator of choledocholithiasis and of liver metastases in anicteric patients.

4-When serum LAP is increased, urine LAP is almost always increased, but when urine LAP is increased, serum LAP may have already returned to normal.

Precautions

make sure that a 24-hour urine sample has been collected

24-hour urine sample collection instructions

• On day 1, urinate into the toilet when you get up in the morning.

• Afterward, collect all urine in a special container for the next 24 hours.

• On day 2, urinate into the container when you get up in the morning.

• Cap the container. Keep it in the refrigerator or a cool place during the collection period.

• Label the container with your name, the date, the time of completion, and return it

Interferring factor

1-Testing serum LAP is generally not as sensitive or as convenient as testing other liver enzymes to detect some liver problems. ALT, AST, ALP, LDH, and GGT are more commonly measured for the same purpose. Unlike other liver enzymes, LAP can be measured in the urine.

Pre analytical errors

If the sample was not collected with the correct instructions ,it will affect the result

The corrective action

The patient must be given the instructions that the sample must be collected, and before taking the sample make sure that he follows these instructions

Post-analytical errors

1- Write another patient’s name on the report

The corrective action

Make sure you write the correct name on the report

2-Writing a wrong result in the report

The corrective action

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, must communicate with him and tell him that an error has occurred and replace the report with the report in which there is the correct result .

Reference range

1.0–3.3 U/mL