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HelpTest Code MPHNU Methylphenidate and Metabolite, Random, Urine
Additional Testing Requirements
If urine creatinine is required or adulteration of the sample is suspected, also order ADULT / Adulterants Survey, Random, Urine. For more information, see ADULT / Adulterants Survey, Random, Urine.
Specimen Required
Supplies: Sarstedt Aliquot Tube 5 mL (T914)
Collection Container/Tube: Plastic urine container
Submission Container/Tube: Plastic, 5-mL tube
Specimen Volume: 5 mL
Collection Instructions:
1. Collect a random urine specimen.
2. No preservative.
Additional Information:
1. No specimen substitutions.
2. STAT requests are not accepted for this test.
3. Submitting less than 1 mL will compromise the ability to perform all necessary testing.
Useful For
Monitoring urine methylphenidate and ritalinic acid concentrations to assess compliance in patients
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Methylphenidate and Metabolite, USpecimen Type
UrineSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 10 days | |
| Frozen | 28 days |
Reject Due To
| Gross hemolysis | OK |
| Gross icterus | OK |
Clinical Information
Methylphenidate (MPH) is utilized for the treatment of attention-deficit hyperactivity disorder and narcolepsy. MPH has two chiral centers and is marketed as a racemic mixture and as the active d-enantiomer of racemic MPH. Although the exact mechanism of its action has not been fully defined, it blocks the reuptake of norepinephrine and dopamine into the presynaptic neuron thus increasing the concentrations of these monoamines in the extraneural space.
Reference Values
Negative
Cutoff concentrations by liquid chromatography tandem mass spectrometry:
Methylphenidate: 10 ng/mL
Ritalinic Acid: 50 ng/mL
Interpretation
Methylphenidate (MPH) has an oral bioavailability of 22% to 100% with peak concentrations occurring around 2 hours for instant release and approximately 5 to 6 hours for extended-release formulations. The half-life of MPH is 2 to 4 hours. MPH is extensively metabolized to ritalinic acid, which is an inactive metabolite. The half-life of ritalinic acid is about 3 to 4 hours. Only small quantities (<1%) of unchanged MPH appear in the urine as most of the dose (60%-86%) is excreted in the urine as ritalinic acid. The presence of MPH or ritalinic acid in the urine indicates the patient has taken MPH in the past 1 to 2 days.
Cautions
No significant cautionary statements.
Method Description
The urine sample is centrifuged, diluted with internal standard and clinical laboratory reagent water, and then analyzed by liquid chromatography tandem mass spectrometry.(Unpublished Mayo method)
Day(s) Performed
Monday, Wednesday, Friday
Report Available
2 to 4 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80360
G0480 (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| MPHNU | Methylphenidate and Metabolite, U | 104676-2 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 608882 | Methylphenidate by LC-MS/MS | 20548-4 |
| 608883 | Ritalinic Acid by LC-MS/MS | 72790-9 |
| 608884 | Methylphenidate Interpretation | 69050-3 |