Clinics and Departments

Laboratory Services

Lab Dept:

Chemistry

 

Test Name:

L-ASPARAGINASE ACTIVITY

General Information

Lab Order Codes:

LASP

Synonyms:

Asparaginase Level; L-Asparaginase Assay

CPT Codes:

82657 x2 – Enzyme activity in blood cells, cultured cells, or tissue, not elsewhere specified; nonradioactive substrate, each specimen

Test Includes:

L-Asparaginase activity reported in mIU/mL.

Logistics

Test Indications:

To monitor levels of L-asparaginase in patients treated with pegglylated or non-peggylated L-asparaginase drug substances including Oncaspar, Elspar, Kidrolase or Erwinase.

L-asparaginase is a high molecular weight enzyme which often induces an immune response in a significant percentage of treated patients. As a result, hypersensitivity to L-asparaginase is a clinically relevant issue regardless of the source from which the drug is prepared

There are two forms of hypersensitivity to asparaginase in the clinic.
Clinical hypersensitivity ranges from a mild local rejection to full blown anaphalaxis. Since asparaginase derived from E.coli is frequently used as first treatment, patients who develop such a reaction are switched to Erwinaze (derived from Erwinia chrysanthemi) to continue their treatment because of a lack of cross-reactivity of anti-E.coli antibodies to Erwinaze. The second form of hypersensitivity is when antibodies are formed, but the patients do not experience any clinical signs of hypersensitivity. Yet these antibodies can either inactivate the enzyme or enhance the metabolism of asparaginase such that the patient may not have adequate serum/plasma activity levels to achieve an anti-leukemic effect (often referred to as “silent inactivation” or “silent hypersensitivity”).

Testing will help clinicians identify these patients as well as to ensure adequate asparaginase activity is present during asparaginase treatment. The patient sample is obtained after treatment to be submitted for the L-Asparaginase assay.

Lab Testing Sections:

Chemistry – Sendouts

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

2 – 4 days

Special Instructions:

Obtain L-asparaginase Kit (AI BioTech) from the laboratory. Fill out requisition form to accompany specimen to the lab. Contact the lab for a kit.

Specimen

Specimen Type:

Blood

Container:

Red top tube

Draw Volume:

2 mL blood

Processed Volume:

0.6 mL serum.

Collection:

Routine venipuncture (following treatment with L-asparaginase)

Note: Leave the stopper intact throughout collection and centrifugation.

Special Processing:

Lab Staff:
1.
Allow specimen to clot a minimum of 30 minutes, but no longer than 60 minutes.
2.
Centrifuge specimen at 3,000 rpm for 15 minutes.
3.
Remove stopper avoiding serum contamination with red cells. Using a disposable pipette, transfer a portion of the serum sample into each of two labeled specimen shipping tubes (available in test kit). Make sure to transfer at least 0.2 mL of serum into each tube.
4.
Record the sample collection date/time on the sample collection form/requisition that accompanied the specimen.
5.
Ship the samples with information provided within the kit. Ship Monday – Thurs overnight express. Specimens can be held at refrigerated temperatures up to 5 days in the refrigerator.

Patient Preparation:

Post-treatment with L-asparaginase

Sample Rejection:

Mislabeled or unlabeled specimens

Interpretive

Reference Range:

None, physician evaluation

 

Critical Values:

N/A

 

Limitations:

N/A

Methodology:

Coupled enzymatic assay

References:

AIBiotech website, 2014



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