Monitoring urine methylphenidate and ritalinic acid concentrations to assess compliance in patients
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
MPH
Ritalin
Concerta
Focalin
Biphentin
Urine
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.
Supplies: Sarstedt 5 mL Aliquot Tube (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. STATS are not accepted for this test.
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.
1 mL
Gross hemolysis | OK |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 10 days | |
Frozen | 28 days |
Monitoring urine methylphenidate and ritalinic acid concentrations to assess compliance in patients
Methylphenidate (MPH) is utilized for the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. MPH has two chiral centers and is marketed as a racemic mixture and as the active d-enantiomer of racemic methylphenidate. 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. Methylphenidate is extensively metabolized to ritalinic acid, which is an inactive metabolite.
Negative
Cutoff concentrations:
Methylphenidate by LC-MS/MS: 10 ng/mL
Ritalinic Acid by LC-MS/MS: 50 ng/mL
Methylphenidate 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 methylphenidate is 2 to 4 hours. Methylphenidate 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 methylphenidate appear in the urine as most of the dose (60%-86%) is excreted in the urine as ritalinic acid. The presence of methylphenidate or ritalinic acid in the urine indicates the patient has taken methylphenidate in the past 1 to 2 days.
No significant cautionary statements.
1 .Kimko HC, Cross JT, Abernethy DR: Pharmacokinetics and clinical effectiveness of methylphenidate. Clin Pharmacokinetics. 1999 Dec;37(6):457-470. doi: 10.2165/00003088-199937060-00002
2. Ramos L, Bakhtiar R, Tse FL: Liquid-liquid extraction using 96-well plate format in conjunction with liquid chromatography/tandem mass spectrometry for quantitative determination of methylphenidate (Ritalin1) in human plasma. Rapid Commun Mass Spectrom. 2000;14(9): 740-745. doi: 10.1002/(SICI)1097-0231(20000515)14:9<740:AID-RCM938>3.0.CO;2-C
3. Paterson SM, Moore GA, Florkowski CM, George PM: Determination of methylphenidate and its metabolite in urine by liquid chromatography/tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci. 2012 Jan 15;881-881:20-26. doi: 10.1016/j.jchromb.2011.11.007
4. Mulet CT, Arroyo-Moro LE, Leon LA, Gnagy E, DeCaprio AP: Rapid quantitative analysis of methlylphenidate and ritalinic acid in oral fluid by liquid chromatography triple quadrupole mass spectrometry. JChromatogr B Analyt Technol Biomed Life Sci. 2018 Aug 15;1092:313-319. doi: 10.1016/j.jchromb.2018.06.025
5. Langman LJ, Bechtel LK, Meier BM, Holstege C: Clinical toxicology. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1323-1324
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)
Monday, Wednesday, Friday
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
80360
G0480 (if appropriate)
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
MPHNU | Methylphenidate and Metabolite, U | In Process |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
608882 | Methylphenidate by LC-MS/MS | 20548-4 |
608883 | Ritalinic Acid by LC-MS/MS | 72790-9 |
608884 | Methylphenidate Interpretation | 69050-3 |
Change Type | Effective Date |
---|---|
New Test | 2021-05-11 |