concerta in regards to UDS results

[deleted1100659]

I know concerta can be missed on UDS but how often do you guys see it test positive for amphetamines? Im seeing a lot of conflicting data when I search. How often do you see it test neg/pos for methamphetamines?

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[Merovinge]

Never seen it test positive for meth, I think there is a very rare chance it can test positive for amphetamines. The reality of methylphenidate is that you need to do send outs for GC/MS to confirm presence reliably. Any positive testing for meth or amphematines should already be triggering a send-out from where you are getting this testing done, particularly if the patient is on Concerta and you are worried they may be using other stimulants.

 

[deleted1100659]

Never seen it test positive for meth, I think there is a very rare chance it can test positive for amphetamines. The reality of methylphenidate is that you need to do send outs for GC/MS to confirm presence reliably. Any positive testing for meth or amphematines should already be triggering a send-out from where you are getting this testing done, particularly if the patient is on Concerta and you are worried they may be using other stimulants.

sounds good; i believed it would be negative too on regular UDS but then I started doing some reading online and second guessing myself and some of reports of it having corssreactivity with amphetamines but wasn't sure if that was even common

with the patient population I treat, never really know. Ive seen lots of weird stuff...

 

[TexasPhysician]

Methylphenidate can cause false positives for amphetamines and LSD

 

[calvnandhobbs68]

Yeah anything weird on a UDS should just be sent out for GC/MS. Cant argue with mass spec results.

 

[Merovinge]

Yeah anything weird on a UDS should just be sent out for GC/MS. Cant argue with mass spec results.

This really should not be a problem for psychiatrists. It is a huge problem for surgeons/anesthesiologists where they utox AM of the surgery and are not able to get results back of GC/MS prior to the start of the case. Particularly in places with high rates of meth/cocaine use, I'm very thankful I never have to make those decisions. Even when you tell people they may die if they are lying about their use there's a significant minority that will still lie, such is the shame and nature of addiction.

 

[Taddy Mason]

This really should not be a problem for psychiatrists. It is a huge problem for surgeons/anesthesiologists where they utox AM of the surgery and are not able to get results back of GC/MS prior to the start of the case. Particularly in places with high rates of meth/cocaine use, I'm very thankful I never have to make those decisions. Even when you tell people they may die if they are lying about their use there's a significant minority that will still lie, such is the shame and nature of addiction.

….or surgery orders a Utox for AMS 1-2 days post-op and then consults the addiction service for suspected SUDs because it comes back positive for benzos, opioids, and fentanyl in a patient with no known Hx of or other reasonable suspicion for substance misuse….

The specificity for the cocaine assay is extremely high (mid to upper 90s%) and I can’t think of a reason for GC/MS if it comes back positive (other than in forensic cases), especially given the cost that has a fair likelihood of falling 100% on the patient. If positive, 99.9999% of the time the patient is either not telling the truth or used something with coke in it.

 

[Merovinge]

….or surgery orders a Utox for AMS 1-2 days post-op and then consults the addiction service for suspected SUDs because it comes back positive for benzos, opioids, and fentanyl in a patient with no known Hx of or other reasonable suspicion for substance misuse….

The specificity for the cocaine assay is extremely high (mid to upper 90s%) and I can’t think of a reason for GC/MS if it comes back positive (other than in forensic cases), especially given the cost that has a fair likelihood of falling 100% on the patient. If positive, 99.9999% of the time the patient is either not telling the truth or used something with coke in it.

I'm not as knowledgeable about the coke part of things since where my wife was running into this problem was methyl meth meth funland. Unfortunately, there are certainly false positives for meth. People seemingly decide believing the patient or not based on "does this person look like they do meth?" which is wild to me.

 

[Stagg737]

I'm not as knowledgeable about the coke part of things since where my wife was running into this problem was methyl meth meth funland. Unfortunately, there are certainly false positives for meth. People seemingly decide believing the patient or not based on "does this person look like they do meth?" which is wild to me.

Cocaine and THC have very high PPV. If a UDS comes back positive, they used it. Benzos have pretty good PPV but often miss some, for example our hospital’s UDS doesn’t pick up Klonopin. However, sertraline can also cause false positives and I’ve actually seen it a couple times. Amphetamines and hallucinogens I usually question d/t false positives. LSD is particularly useless if it’s even included.