Because its useful to have these data from a scientific perspective. Say for example you have leukemia later in life. A researcher wants to study what it is about your leukemia that makes it different from the rest of your blood. You can't solve that problem by drawing blood from the patient today, all the blood will be contaminated with leukemia. You could try and get DNA from the fingernails, but these are liable to be of poor quality and damaged by environmental factors that fingernails tend to be exposed to. Likewise for most other blood free sources of DNA you could take from a living person.

Now, if you had a blood sample from before the patient had leukemia, that would be invaluable data. You can yield high fidelity genetic material without much blood sample. Because of this, most states have laws saying this newborn screening material is available for various research purposes. The parent or the individual may also request their newborn sample, should new screening methods come out in the future that may not be on that panel when you were born for example.

https://www.cdph.ca.gov/Programs/CFH/DGDS/CDPH%20Document%20...

> Say for example you have leukemia later in life. A researcher wants to study what it is about your leukemia that makes it different from the rest of your blood.

That could still be done if the data/samples were anonymized and the ID were only given to the patient. For general research, anonymized would also work perfectly fine.

It is anonymized when its used for research purposes, but you still would want to have some key to match it up to the patient should they have more information to add down the road. Say the patient took some drug for their leukemia and had remission, that is valuable metadata to include along with the raw sequence data in a database.

After public evidence of usage like this, who would believe that ID was only given to the patient?

That's why data protection and privacy laws are needed first.

Could be a cord blood banked collection that some parents consent to (and pay for).

https://www.stanfordchildrens.org/en/topic/default?id=cord-b...

Edit: about half way through the article, it appears to be a sample from newborn screening, but another thing to think about.

They just need to shorten the TTL.

Liberals will support it because public health.

Conservatives will support it because law and order.

It's the perfect storm of governmental invasiveness.

Deleting (destroying) everything after all tests have been done would be the simple solution.

No such thing. Any data that can be saved, will be saved. Deletion is a myth.

Well yes, because there are no laws and punishments which would disincentivize it.

What's the public health benefit to keeping blood samples around for so many years?

There are diseases (particularly cancer) that can be detected before symptoms arise based on the changes in the methylation of the DNA present in cells in the plasma.

To detect these, you need to have a baseline - the longer the better.

For one such study, The Project Baseline Health Study: a step towards a broader mission to map human health --- https://www.nature.com/articles/s41746-020-0290-y

> Further, while some participants’ samples have been assayed with a broad array of tests (Tables 2–4), participant samples will be stored for in depth testing at a later time when current assays are pertinent or new assays are available or new understanding of a disease process make performing a standard assay, not originally done, to be done on all or a sub-group of participants because of this new knowledge.

Research is the big/obvious one.

Improper caching?