The FirstStepDx PLUS® Difference

FirstStepDx PLUS is optimized compared to other chromosomal microarray (CMA) tests.

Lineagen makes genetic testing easy with comprehensive services and support:
  • We handle the whole insurance process, from preauthorizations to appeals
  • We provide unlimited access to genetic counselors
  • We use a cheek swab, so getting a sample is painless for everyone

Lineagen uses proprietary processes to ensure critical genetic information is not missed: 
  • FirstStepDx PLUS delivers high detection rate by providing comprehensive interpretation and reporting
  • We developed an exclusive variant information program, PrismDx, to optimally process, understand and report variants for clinical use
  • We monitor the literature for discoveries that could change your patients’ test results, and we reach out to you when appropriate

Learn More

Rena Vanzo MS, LCGC Licensed & Certified Genetic Counselor,
Vice President, Clinical Services, Lineagen, Inc.

Read More: Lineagen uses a painless cheek swab for sample collection

In most cases, when a provider orders a genetic test, blood collection is the gold standard in genetic testing. It's common practice to use blood samples and it has been for a long time.

However, many families aren't getting their child tested because blood draw just isn't an option for them. We've heard from many providers that they've stopped ordering certain tests because families refuse to put their child through a blood draw.

Blood draws can be traumatic for children

Blood draws can be particularly traumatic for children with developmental disabilities who have certain hypersensitivities. With Lineagen's FirstStepDx PLUS testing, we have elected to validate a buccal cheek swab DNA collection and use that rather than blood collection for our CMA.

We've chosen to use the buccal swab for three main reasons:

Ease of collection

The first is the ease of collection. No one enjoys having their blood drawn. And a cheek swab is much more familiar territory for a child. Parents will often help with the collection of the DNA and incorporated collection with a daily routine such as pretending to brush their teeth.

That's something the child isn't threatened by. It's something mom or dad can easily help with in the office. It's much easier to use and it can be done right there in the evaluation room and the family doesn't have to go halfway across the medical campus or down the road to a phlebotomy station.

Cheek swab samples are much more stable than blood

In addition to ease of collection, the DNA collected from a cheek swab can be stable for much longer than a blood draw. Clinicians ordering a blood draw for a patient need to worry about numerous factors:

  • Is it shipped overnight?
  • Does the sample have to be on ice or dry ice?
  • What's the temperature outside?
  • Will there be potential shipment delays?

Cheek swabs are stable for two months at room temperature

With the DNA cheek swab used by Lineagen, the stability of that sample lasts up to two months (60 days). Room temperature is the best way to ship and store the sample and provides us with flexibility so that we can do the necessary work with the insurance and contact the family. A blood sample requires refrigeration and will only last a few days. There is not the time restriction that we would have if we were handling a blood sample.

The cheek swab is technically better than blood for this type of genetic testing

The third reason why the cheek swab is preferred over the blood draw for our CMA service is because the results are actually technically better from the cheek swab. An example is the detection rates for mosaicism and mosaic syndromes such as mosaic trisomy 21 or mosaic Turner's syndrome. Lineagen has reported a result in which we found 20% mosaic trisomy 21 in the buccal sample while the blood sample from the same individual only showed 5% mosaicism1

If only the blood was tested in this individual, that diagnosis would've been missed. And of course having a diagnosis of trisomy 21 is very critical for a provider to know so that the child can be put on a special healthcare supervision plan to monitor for the risks associated with Down syndrome.

1. Data on file

Rena Vanzo MS, LCGC Licensed & Certified Genetic Counselor,
Vice President, Clinical Services, Lineagen, Inc.

Read More: Lineagen provides access to genetic counselors when needed

Lineagen makes genetic counseling and genetic counselors a central part of our CMA process. Providers can contact our team of genetic counselors at any time to ask questions about the appropriateness of testing or clarification on test results.

We get frequent calls from doctors

For example, we get frequent call from physicians about whether our test can diagnose Marfan syndrome or neurofibromatosis type-one. Neither condition is diagnosable by CMA testing and we are always happy to have to opportunity to clarify that with physicians rather than have them misread the results on the test.

If a physician is questioning a certain diagnosis, we welcome calls to ask us about the probe coverage of our microarray for that particular condition. Our genetic counselors can also answer questions about CMA's that may have been done on a patient in the past and how that CMA compares to our CMA.

Genetic counselors on call

We have genetic counselors who are on call available to answer questions from healthcare providers at any time, even while the patients are there in the office. We don't want the family to have to leave and make another appointment and we realize how important it is for physicians to have those answers right away.

Follow-up on abnormal results

Our genetic counselors will contact physicians each time an abnormality is identified and reported out to the physician.

We encourage doctors and patients to call with questions

Our genetic counselors are available to provide pre-test and post-test counseling for any patient or family.

Why is variant interpretation important when choosing a lab?

Detecting a variant is only part of the solution. It is critical to ensure that variants found are interpreted correctly and all the clinical information known about it is well-reported. Optimal diagnosis and management depend on how well variant results are understood. 


“...assessing the clinical significance of CNVs [copy number variants] found in a clinical setting can be challenging...interpretation and reporting practices may vary among laboratories.”
- American College of Medical Genetics (ACMG)1 

Lineagen invested in the Variant Information Program, PrismDx, to deliver accurate interpretation and improved clarity for variants identified, especially CNV variants of unknown significance (VOUSs).

What is PrismDx?
By bringing together critical methods of interpretation (fig. 1) and a multidisciplinary team of experts, Lineagen's PrismDx is able to deliver clinical information on genetic variants not available to and reported by other labs.

Figure 1.

What is the proprietary variant index?
The variant index, one of the exclusive interpretation tools in PrismDx, identifies gene regions that are highly expressed and not frequently mutated in the brain and, when disrupted, are likely causal for ASD and DD. Identification of these regions allows Lineagen to assign greater clinical importance to lesser known genetic variants, which has resulted in additional insight for >40% of VOUSs.2


1. Kearney HM, et al.; Genet Med. 2011 Jul;13(7):676-9.
2. Uddin, M., et al., Nature Scientific Reports, 2016, 6, 28663
Rena Vanzo MS, LCGC Licensed & Certified Genetic Counselor,
Vice President, Clinical Services, Lineagen, Inc.

Read More: Lineagen monitors the literature for findings that could affect your patients

When a CMA test is ordered, there are three main result outcomes: negative, pathogenic/abnormal and variants of unknown significance. A negative result means no genetic abnormality was identified. A pathogenic or abnormal result signifies that something was identified that has a medical impact for the child. A variant of unknown significance indicates that a genetic variation was identified but the clinical significance of the variant is currently unclear.

New genetics data are published every day

We want our ordering providers to have available information about these variants of unknown significance. Genetics is expanding and publications are coming out every day and what is unknown today may be known tomorrow. All syndromes started with some level of uncertainty about what this condition is.

How to receive updates on variants

If you have questions about whether new information is available about a variant, please contact Lineagen’s genetic counseling team. A genetic counselor can discuss the options available to re-investigate a variant. If a variant was reported on a previous FirstStepDx PLUS CMA, a genetic counselor can research the current literature and our extensive patient database to determine if new evidence is available. Other options may be available for variants reported on NextStepDx PLUS whole exome sequencing.

Additionally, every time Lineagen reports a variant, we review our patient database to determine if it has been previously reported. If there is new evidence available that impacts the understanding of the variant, Lineagen will issue an update letter to the physicians and/or families of those previous patients. This letter will summarize the new evidence, how it impacts the clinical significance, as well as how to contact our genetic counseling team for further discussion.

We have genetic counselors who are on call, available to answer questions from healthcare providers at any time, even while the patients are there still in the office.
Rena Vanzo
MS, LCGC Licensed & Certified Genetic Counselor,
Vice President, Clinical Services, Lineagen, Inc.