According to the National Institute of Justice 50 States have laws in place that authorize the non consensual taking of DNA samples from humans convicted of certain crimes however there are 28 States that authorize DNA sample taking prior to conviction. In this case the involuntary sample is authorized at arrest.
These laws are being challenged.
The actual circumstances that pre-empt the sample taking vary from state to state. States that do not have these laws are required to obtain a court order authorizing them to take DNA samples prior to conviction of a crime.
The Fourth Amendment (Amendment IV) to the United States Constitution is the part of the Bill of Rights which guards against unreasonable searches and seizures, along with requiring any warrant to be judicially sanctioned and supported by probable cause. It was adopted as a response to the abuse of the writ of assistance, which is a type of general search warrant, in the American Revolution. Search and seizure (including arrest) should be limited in scope according to specific information supplied to the issuing court, usually by a law enforcement officer, who has sworn by it. The Fourth Amendment applies to the states by way of the Due Process Clause of the Fourteenth Amendment.
DNA Sample Collection from Arrestees
On this page find:
Overview of Arrestee DNA Collection Laws
Figure 1. States That Have Enacted Arrestee DNA Collection Laws in the United States
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The federal government and 28 states (as of June 2012) have enacted arrestee DNA collection laws, which authorize collection of DNA following arrest or charging. 
Louisiana passed the first state arrestee DNA collection law in 1997. Four other states followed suit before Congress passed the DNA Fingerprint Act of 2005. The Act required that, beginning January 1, 2009, any adult arrested for a federal crime must provide a DNA sample. Since 2005, an additional 23 states have enacted arrestee DNA collection laws. (click image to enlarge )
Which offenses are eligible for collection?
Of the 28 state laws authorizing arrestee DNA collection, 13 collect samples from anyone arrested for a felony; the rest limit collection to violent crimes, including sexual assaults. Seven states also collect samples in certain misdemeanor cases.
When can a sample be collected or analyzed?
Most states authorize DNA collection at arrest. Only 11 states require an arraignment or judicial determination of probable cause before a sample can be collected or analyzed.
What other DNA collection laws exist?
All 50 states and the federal government have laws that require certain convicted offenders to provide a DNA sample for inclusion in CODIS (the federal Combined DNA Index System database) and state databases.
NIJ funded the Urban Institute to examine how key provisions in arrestee DNA legislation influence the logistical activities associated with DNA collection and analysis. The study involves a review of state and federal laws along with interviews of state crime laboratory representatives in 26 of the 28 states that passed legislation authorizing collection of DNA from some subset of arrestees. Although the study is ongoing, the Urban Institute provided some preliminary findings that are current as of June 2012.
The researchers identified the following three key logistical issues that most states with arrestee DNA laws have addressed:
Responsibility for collection
Most state legislation specifies which agencies should collect arrestee DNA. Of the 17 states that designate a particular type of agency in their DNA legislation, most specify the arresting agency, booking agent, detention center, sheriff or jail as having primary responsibility.
Policies governing duplicate samples
Some states do not have systems in place to avoid collecting duplicate samples from people who have been arrested previously. This can involve a significant cost for unnecessary collection and analysis of samples. Collection is estimated at $4 to $6 per kit, and analysis is estimated at $20 to $40 per sample. The proportion of duplicate samples may be as high as 50 percent.
Responsibility for expungement
All states have processes in place for expunging a DNA profile if a charge is dismissed or results in acquittal. In most states, the person who was arrested is responsible for initiating the process. Interviews with crime lab officials show that very few people initiate the process, so their profiles remain in the databases.
The Urban Institute also identified a number of challenges for states that choose to collect DNA from arrestees:
- Verifying that a sample is eligible for collection and determining if it would be a duplicate can be time consuming, especially for agencies that have older data systems.
- Laboratories in states that require a judicial determination of probable cause may have to spend considerable time and money tracking cases. The same is true for states that automatically expunge DNA profiles.
- The sheer volume of samples can be difficult to manage.
- States that decide to collect arrestee DNA samples can expect to spend money to hire and train additional staff, develop training materials and add new data systems.
To learn more about the Urban Institute’s research, see Collecting DNA From Arrestees: Implementation Lessons. The final report from this grant is expected in late 2012.
 Not all states that enacted arrestee DNA laws still collect arrestee DNA. In some states, arrestee DNA collection laws have faced Fourth Amendment challenges in court, with mixed results. The Supreme Court of Virginia upheld the state’s law in 2007; the Minnesota Court of Appeals, a California appellate court and the Maryland Supreme Court found the law unconstitutional. The rulings in California and Maryland are being appealed.