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Frequently Asked Questions

Questions? We have answers.

Why should you choose urine drug analysis?

Urine drug testing has been the preferred biologic specimen or gold standard for determining the presence or absence of most drugs since its inception. This is, in part, due to the increased window of detection of 24 to 72 hours for most drugs and/or their drug metabolites. Since urine specimens have a longer detection window this means that a patient’s usage can be detected for a longer duration of time. Drug metabolites are more frequently found in urine specimens; therefore, a urine drug testing lab can assist physicians in readily determining if their patients are staying compliant with prescribed medications and treatment plans.

How are specimens delivered to the laboratory?

Gulfstream Diagnostics utilizes FedEx® as our courier service of choice. For specimen pick up, please call 800.GOFEDEX or contact your Account Manager.

Why are screening and confirmation cutoff levels different?

Screening and confirmation testing are performed using different methodologies that necessitate different cutoff levels. The cutoff levels of an immunoassay screen are typically higher than those of a more sensitive LC-MS/MS confirmation test, because they screen for a larger group of parent compounds, metabolites and other structurally similar compounds.

When can I expect to see the drug test report?

Urine screening results are typically available within 1 business day of receipt of the specimen. Presumptive positive specimens are usually confirmed (unless they are "Screen Only") within 2 business days, depending on the method.

How long does Gulfstream Diagnostics store the specimen?

Gulfstream Diagnostics stores urine and oral fluid specimens, whether positive or negative, for 60 days, and blood specimens for 7 days.

What is the importance of checking the urine temperature strip on the collection cup?

Under normal conditions fresh urine will display a temperature between 90 and 100 degrees Fahrenheit on the temperature strip, if read within four minutes of the collection. Should the temperature strip not register, the specimen should be immediately re-checked using a new cup (or strip) and the results recorded on the requisition. Specimens with a temperature out of range may indicate a substituted or adulterated specimen.

What is the importance of checking urine creatinine levels?

Creatinine is a metabolic by-product of muscle metabolism, and normally appears in urine in relatively constant quantities over a 24 hour period with "normal" liquid intake. Therefore, urine creatinine can be used as an indicator of urine water content (dilution) or as a marker identifying a specimen as urine. Greater than normal intake of water will increase the urine water content (lowering the creatinine level) consequently diluting any drug which may be present in urine. Conversely, a limited intake of water can lead to an abnormally concentrated urine specimen (as occurs with dehydration) resulting in elevated creatinine levels.

What is the point of doing LC-MS/MS when we’ve already done a urinary point-of-care test?

LC-MS/MS is more sensitive and specific than the urinary point-of-care test. Drugs are separated along size and charge metrics. Both parent drugs and fragmented analytes are identified using the tandem mass spectrometer’s computer. From there, the information may be accessed at any time.

In contrast, point-of-care tests are immunoassays. They can lead to false positives and false negatives, especially in individuals with heterophile antibodies due to severe illnesses or autoimmune diseases. It is possible for those antibodies to impact the ways in which drugs “attach” themselves inside the body. Likewise, HAMA bodies, contracted by rodent bites, may lead to false positives and negatives.

Why have I received a bill when I have insurance to cover my laboratory testing?

There are a few reasons this may have happened:

  • Insurance information was not received with the test order
  • Insurance information was incorrect or could not be confirmed with the carrier
  • The insurance carrier processed the claim and denied payment
  • The insurance carrier processed the claim and applied the balance to your co-pay or deductible

Please refer to the explanation of benefits (EOB) from your insurance carrier for more specific information. If you have additional questions or concerns about your coverage, please contact your insurance carrier directly. If you have updated/corrected insurance information, please send the correct insurance information to us by faxing a copy of the invoice and copy (front and back) of your insurance card to 972.630.6411 or mail to:

Gulfstream Diagnostics, LLC
Attn: Billing Department
9301 N. Central Expressway
Tower 2, Suite 335
Dallas, Texas 75231

Upon receipt of the new insurance information, we will resubmit the claim to your insurance carrier.

Why did I receive a bill from Gulfstream Diagnostics?

Gulfstream Diagnostics received information from either your insurance carrier or the ordering physician/facility that the patient is responsible for all or part of the charges. For help understanding your bill, please contact the Customer Service phone number listed on your invoice.

My insurance information has changed. How do I correct it?

You can submit your insurance information directly to Gulfstream Diagnostics. Please send a copy of your insurance card (front and back) to Gulfstream Diagnostics by fax to 972.630.6411 (Attention: Billing Department) or by mail to:

Gulfstream Diagnostics, LLC
Attn: Billing Department
9301 N. Central Expressway
Tower 2, Suite 335
Dallas, Texas 75231

Please be sure that the information provided is accurate, complete and legible. Inaccurate or incomplete information may result in a delay or denial of payment by your insurance carrier. You can also mail or fax a copy of the front and back of your insurance card to the correspondence address or fax number listed on your invoice.

What if I cannot afford to pay my bill?

Gulfstream Diagnostics understands that medical bills can be a hardship for some patients. We offer a financial assistance program to individuals who qualify. Refer to our Financial Assistance Program or contact the Customer Service phone number listed on your invoice to discuss options available. You may also download the application here.

Submit completed applications, with supporting documentation to:

Gulfstream Diagnostics, LLC
Attn: Collections Department - FAP
9301 N. Central Expressway
Tower 2, Suite 335
Dallas, Texas 75231

I received a check from my insurance company, can I cash the check?

In some instances, one of Gulfstream Diagnostics' labs will file as an out of network provider with your insurer. The carrier may send payment directly to you instead of us. If you receive payment for our laboratory services, please contact us to arrange payment or remit payment to us by writing the lab on the back of the check,

  • "Payable to Laboratory Services of East Texas" or
  • "Payable to East Texas Referral and Testing" then sign and mail the check and copy of the EOB to:

Gulfstream Diagnostics, LLC
Attn: Billing - Insurance Reimbursement
9301 N. Central Expressway
Tower 2, Suite 335
Dallas, TX 75231

Can Gulfstream Diagnostics tell me how much I can expect to pay for my tests?

The price you pay for tests performed by East Texas Referral and Testing or Laboratory Services of East Texas will depend on several variables, such as:

  • If you have insurance or not
  • Your insurance plan coverage of laboratory tests
  • Eligibility for financial assistance

Why did my doctor test me?

It is recommended that physicians nationwide implement and maintain a comprehensive, therapeutic drug-monitoring program. To achieve this, your physician will ask for a sample to accurately identify the drugs within your system. This ultimately provides a more complete treatment program for you.

I received an invoice requesting additional information. What should I do?

Please send the requested information to the address or fax number listed on your invoice. You can also call the Customer Service phone number listed on your invoice. If the message on your invoice indicates that your insurance carrier needs more information from you in order to process your claim, please contact your insurance carrier directly.

What can I do when my claim is denied due to the diagnosis code?

Diagnoses are provided by the ordering physician's office. If your claim was denied due to the diagnosis code, please contact your physician's office.

My claim was denied for coordination of benefits. What do I need to do?

Your insurance carrier has identified you as having more than one insurance carrier and the insurance provided to us is not the primary payer. Please send a copy of your primary insurance card (front and back) to Gulfstream Diagnostics by fax to 972.630.6411 (Attention: Billing Department) or by mail to:

Gulfstream Diagnostics, LLC
Attn: Billing Department
9301 N. Central Expressway
Tower 2, Suite 335
Dallas, Texas 75231

If you do not have other coverage, please contact your insurance carrier to update their records.

Does Gulfstream Diagnostics have help for patients experiencing financial hardship and/or patients who do not have insurance?

Gulfstream Diagnostics offers a comprehensive payment support plan and financial assistance program, which includes:

  • Free or reduced-fee laboratory services, to those who qualify based on U.S. Department of Health and Human Service poverty guidelines
  • Prompt payment discounts
  • Payment plans - allows patients to pay in monthly installments until their balance is paid in full

Will patient collections affect my credit score?

Gulfstream Diagnostics' complies with the Fair Debt Collection Practices Act for all collection activities and, at this time, does not take actions that will negatively affect the patient or guarantor's credit history.

My physician said I would not have to pay anything. Why did I receive a bill?

Your physician sent tests to Gulfstream Diagnostics, an outside lab, and our charges are outside any financial arrangements you may have made with your physician or clinic.

How do I order supplies?

Visit our online portal at Click the order supplies link at the top right of the website.

When will my supplies arrive?

Supply orders sent prior to 2pm will be shipped the same day. Orders after 2pm are shipped the next business day. Gulfstream generally ships supplies via ground but can accommodate overnight shipping if needed.

How long does it take until I’m up and running?

Complete onboarding is 3-5 business days and is a fully supported process. The team at Gulfstream immediately goes to work for your facility offering all the critical support you need.

Who do I contact with questions?

Please email inquires to Client Services or call us: | (972) 630-6400 | (844) 453-7876.

Please call Client Services directly (or your Client Account Manager) if you have questions that require you to give us a patient name. HIPPA protected information must be encrypted if sent via email.

What are your hours?

Representatives are in the office at 8am – 5pm on Monday – Friday. We also offer after hours support, assuring that your facility will always get the support it deserves.

What type of physician verifications are performed?

Client Services verifies physician NPI numbers, PECOS registration, and a check for Medicare Exclusivity at the time of onboarding.

How do providers get trained on the portal?

The implementation manager will set up a web-based GoToMeeting to ensure the client is trained on how to review results in our ENGAGE portal. On-site training may also be available in some instances.

How do I request a specimen processor or phlebotomist?

Your account paperwork has a space to request a phlebotomist or specimen processor. Please check the appropriate box and allow time for Gulfstream to hire and train the required employee.

If you have a question that hasn’t been answered here, feel free to contact us and speak with one of our toxicology experts.