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General Testing Questions

Sample Requirements


For Hopkins Providers:

General Testing Questions

Do you still offer GNAS methylation testing for pseudohypoparathyroidism type 1b?

No, unfortunately this previously offered test was taken off our test menu for optimization reasons. In the future, if we are able to perform this testing with an alternate assay, an announcement will be made on our website. We are not aware of another clinical lab who is performing GNAS methylation testing at this time.

I cannot find the gene I am looking for on your test menu; can you custom design a test for the gene?

We are unable to custom design a test to sequence the entire coding region of a gene, however, we can custom design a test for a targeted variant in any gene of interest. 

How do I order a targeted variant test?

In order to order a targeted variant test you will need to complete our general requisition form

If your patient has had a family member previously tested at our laboratory, we ask that you either include a copy of their test report (listing the variant) with the requisition form or include the family member’s genetic ID on the requisition form. 

If your patient has never had a family member previously tested at our laboratory, we will need a copy of the report from an outside lab, listing the variant that you wish to target.  We will also need a sample submitted from a known carrier of this variant to use as a positive control.  This additional positive control sample will not add any additional cost to your testing.

Does your lab offer follow-up family variant testing?

Yes, we offer follow-up family variant testing, but for the typical targeted variant test price of $350.  In the case of a variant of uncertain clinical significance (VUS), however, you may qualify for our VUS resolution program at no charge. 

What is your VUS resolution program policy?

Our VUS resolution program involves targeting additional family members for a VUS, with the intention of this additional information aiding in reclassification of the variant.  In order to qualify for our VUS resolution program, your patient must have at least one VUS listed on a test report that was issued by our laboratory.  We will accept up to two informative family member samples for this testing program.  These individuals must be deemed informative by the laboratory.  If testing family members will not help to re-classify a variant then your patient will not qualify for this program.  If you are interested in finding out if your patient qualifies this program, please email our lab at

What is your clinical exome sequencing reanalysis policy?

The ordering provider may request a reanalysis of exome sequencing data either between 1 to 3 years after the original test report was issued or in the case that the patient presents with a significant, clinically relevant change to their phenotype. The first reanalysis falling within these guidelines may be requested at no charge and any subsequent re-analysis will be charged according to current rates. Reanalysis will focus on variants within genes associated with the new clinical manifestations and/or newly identified genes associated with the subject's original clinical features. The reanalysis may also disclose newly designated pathogenic or likely pathogenic variants based on new information.  Variant interpretation will be based on current literature and data in public databases combined with phenotype information provided by the ordering provider. Of note, reanalysis may also reveal newly designated likely pathogenic or pathogenic variants in genes deemed medically actionable by the ACMG (i.e., secondary findings). We will communicate new secondary findings if your patient consented to receiving this information. This policy is subject to change in the future.

How do I get my results for telomere length testing?

The DNA Diagnostic Lab does not perform telomere length testing; we only perform short telomere-related genetic testing. In order to retrieve results for telomere length testing, please contact the Molecular Diagnostic Lab at the phone or email found here:

Sample Requirements

What is the stability of a blood sample that I would like to ship to you?

If we are expected to receive the blood sample in our lab within 36 hours of draw, the sample can stay ambient (room temperature).  If we are expected to receive the sample in our lab after 36 hours from draw, the sample should be refrigerate and shipped with a cold pack.

I noticed that your test requisition form asks about whether the patient has had a transfusion.  Why do you need to know this information/how will it affect genetic testing?

In certain situations, a transfusion can impact the accuracy of genetic test results.  If your patient has had a packed red blood cell (PRBC) transfusion, you can still collect/send a sample, as this will not affect genetic testing.  If your patient has had any other type of transfusion, you must wait until at least 2 weeks after the transfusion date to collect a sample for genetic testing.  If you have any further questions about this please contact the lab at

Can I send a blood sample for genetic testing if my patient previously had a bone marrow transplant?

No, if someone previously had a bone marrow transplant, genetic testing results from a peripheral blood sample would be representative of the donor’s cells, not the patient.  In this case, we recommend sending DNA extracted from cultured fibroblasts.  If you have any further questions about this please contact the lab at


If my patient has two variants that I would like to target, would they have to pay $350 per variant?

No, our targeted variant price of $350 can cover multiple targeted variants tested within the same patient.  If your patient carries multiple variants, whether in the same or different genes this would still only be one fee of $350.

How do I find out which price and CPT code you list for your tests?

Price and CPT code information for all of our offered tests can be found here.

Is prior authorization required for testing?

Prior authorization is required for all exome and zoom testing.  All prior authorizations should list the Johns Hopkins Genomics DNA Diagnostic Lab as the laboratory providing the service.

Who is responsible for obtaining the prior authorization?

The referring provider/physician typically initiates the prior authorization request through your insurance company on your behalf.  However, it is your responsibility to follow-up and make sure that you have prior authorization before any samples are sent to the lab.

For Hopkins Providers:

If I am sending genetic testing for an inpatient, do I need to get prior authorization?

No, you do not need to get prior authorization for inpatients.  This testing will be lumped into their hospital bill.

If I am sending genetic testing for an outpatient, do I need to get prior authorization?

Yes, you will need to contact the billing coordinator prior to sending genetic testing for an outpatient in order to get prior authorization initiated.  Before sending a sample for testing, contact our billing coordinator at and provide the following information:

  • Patient Name
  • Patient DOB
  • Patient MRN
  • Name of provider ordering the test
  • Type of test being ordered
  • Date of Service

You will receive an email letting you know whether prior authorization has been approved or denied (this can take anywhere from a few days to over a month).

If you were unable to find the answer to your question, please contact and we would be happy to help!!