Sign in →

Test Code MPHNS Methylphenidate and Metabolite, Serum


Ordering Guidance


This test should only be ordered by healthcare professionals to monitor patients who have been prescribed methylphenidate or identify misuse/abuse.



Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Red top (Serum gel/SST are not acceptable)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL Serum

Collection Instructions: Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.


Secondary ID

624101

Useful For

Confirming drug exposure and monitoring serum concentrations of methylphenidate and ritalinic acid

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Reporting Name

Methylphenidate and Metabolite, S

Specimen Type

Serum Red

Specimen Minimum Volume

Serum: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Frozen 28 days

Reject Due To

Gross hemolysis OK
Gross lipemia 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 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.

Reference Values

Methylphenidate:

4-25 ng/mL (Single-dose peak plasma concentration range in children given 10-15 mg dose)

 

Ritalinic acid:

80-250 ng/mL (Single-dose peak plasma concentration range in children given 10-15 mg dose)

 

Cutoff concentrations:

Methylphenidate: 1.0 ng/mL

Ritalinic acid: 1.0 ng/mL

Interpretation

This test will identify patients who have taken methylphenidate.

Cautions

Specimens collected in serum gel tubes are not acceptable because the drug can absorb onto the gel and lead to falsely decreased concentrations.

Clinical Reference

1. Langman LJ, Bechtel LK, Holstege CP. Clinical toxicology. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:chap 43

2. Baselt RC. Disposition of Toxic Drugs and Chemical in Man. 12th ed. Biomedical Publications; 2020

Method Description

The sample is extracted through protein precipitation, diluted, and then analyzed by liquid chromatography tandem mass spectrometry for the presence of methylphenidate and/or ritalinic acid.(Unpublished Mayo method)

Day(s) Performed

Thursday

Report Available

3 to 9 days

Specimen Retention Time

14 days

Performing 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

G0480

 

80360 (if appropriate for select payers)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MPHNS Methylphenidate and Metabolite, S In Process

 

Result ID Test Result Name Result LOINC Value
624102 Methylphenidate 3807-5
624103 Ritalinic Acid 32153-9