Frequently Asked Questions

COVID-19 Testing FAQs

Toxicology Testing FAQs

Can my business or facility set up a COVID-19 testing account?

Please refer to the Contact Us or call CTR Labs at 240-397-7060. 

What type of COVID-19 test is perform at CTR Labs?

CTR Labs uses a multiplex (3 genes) real-time reverse transcription polymerase chain reaction (RT-PCR) test for the qualitative detection of RNA from SARS-CoV-2 virus. This is a molecular diagnostic test which could indicate an active COVID-19 infection.

When can I expect to see my results?

Test results can be expected within 48 hours of collection. 

What type of sample collection is performed onsite?

CTR Labs uses a nasal mid-turbinate swab for collection. See the CDC infographics for more information on this collection method. 

What does a positive COVID-19 result mean?

A positive test result for this assay indicates that RNA from SARS-CoV-2 was detected, and the patient in infected with the virus and presumed to be contagious. Patient management should follow current CDC guideline.  

What does a negative COVID-19 test result mean?

A negative test result for this assay means that SARS-CoV-2 was not present in the specimen above the limit of detection. A negative result does no rule out the possibility of COVID-19 and should not be used as the sole basis for treatment or patient management decisions. If COVID-19 is still suspected, based on exposure history together with other clinical findings, re-testing should be considered. 

What does an inconclusive COVID-19 test result mean?

An inconclusive test result for this assay indicates another specimen should be collected and tested. 

How are results delivered?

Test results are being transmitted via encrypted email or through our secured web portal.

Is this assay approved by the FDA?

Yes, this test and collection procedure have been authorized by an FDA under the Emergency Use Authorization (EUA).  

How do I sign my practice up for CTR's services?

Refer to the Contact Us page or call 240-397-7060.

When can I expect to see my results?

Urine screening results via EIA are usually available within 24 hours upon delivery to the lab. LC/MS confirmation results will be available within 72 hours upon delivery to the lab. 

How long can the urine specimen stay at room temperature after collection?

We recommend that a sample be sent in within 72 hours of collection. We will accept specimens after this period, but please be advised that specimens will degrade over time and this could affect the detectability of certain drugs. If specimens cannot be shipped within that time period, you may refrigerate the sample for up to 7 days. 

How much urine is needed to perform a comprehensive panel?


Why is there a temperature strip on my collection cup?

Under normal situations fresh urine will display a temperature between 90 and 100 degrees. Specimens with a temperature out of range may indicate a substituted or adulterated sample.

Can I receive a pending report?

Pending reports will be available via the web portal. For example, a pending report may show screen results, but incomplete confirmation results will be displayed as "pending."

How are reports delivered?

The best way to recieve reports is through the web portal, but fax and email through our HIPAA compliant vehicles are also available. 

Why are some results positive on my report, but not highlighted red?

Results are only highlighted red when they are inconsistent with the prescribed medications. This is true for both positive and negative results. 

What does "cutoff" mean on my reports?

Cutoffs are the lowest measurable levels of concentration in which a compound is detectable in the specimen. These levels are specific to each drug and determined by CTR's team.

Why is my screen result positive, but my LC-MS/MS result negative?

Screens use antibodies to detect the presence of a wide range of drugs, whereas, confirmation analysis looks for a specific compound. Furthermore, although very selective, screens can cross-react with structurally similar compounds and give a false positive. Confirmation testing is not subject to this cross-reactivity.

Why are some prescribed medications missing under “Prescribed Medications” on the lab report?

If a prescribed medication was not listed on your patient’s lab report, that typically means it wasn’t selected on the patient requisition form that accompanied the sample.

What does qns mean?

This means Quantity Not Sufficient. The volume of the submitted specimen is not enough to complete the ordered test or tests. 

How long can drugs be detected in the system?

Our in-depth Drug Information Material breaks down the retention times for a wide range of drugs. Here you can find information about specific drugs and their detection times. Click Here to view the Drug Detection Time Window Chart

Do you do oral fluid testing?

No, there are some downsides to consider when choosing oral collection vs urine. The disadvantage is that antibodies in most commercially available immunoassay drug screen tests, including ours, target metabolites. Metabolites are not found in oral fluid. In addition, drugs that are ingested orally (like ethanol) as well as those that can be smoked (i.e., methamphetamine, PCP, marijuana, and cocaine) may be detected in high concentrations in oral fluid following recent use due to residual drugs remaining in the oral cavity. However, under these circumstances, results may not be accurate because the drug concentration found in the oral fluid may not reflect the blood-drug concentration. 

I'm out of supplies. How do I get more?

Refer to the "Order Supplies" page on this website and fill out the required fields. Supplies typically arrive within 2-3 business days.