Can an individual require access to his pre-employment drug screening results in the United States? I am mostly interested in California and Massachusetts.
The federal Health Insurance Portability and Accountability Act of 1996 (HIPAA) may apply to you and provide certain rights. HIPAA does seem to cover part of this, though if it covers you particularly and the lab that performed the test is a separate question.
On the Department of Health and Human Services website discussing HIPAA, they outline requirements discussing pre-employment drug tests. Basically, your authorization is required in order to release the results of the drug test to your employer and there is nothing prohibiting the employer from conditioning employment on your provision of that authorization.
This seems to indicate that the drug test is a medical record.
In another section on the same web site concerning your medical records, it outlines that the Privacy Rule gives you the general right to inspect, review and receive a copy of your medical records if the health care provider is covered by the Privacy Rule.
You can read about the privacy rule on yet another section of that web site. Generally speaking, the privacy rule applies to any health care provider that transmits health records electronically. Certain exceptions to the rule apply, however determining what those exceptions happen to be is a more difficult task.
You will notice from the hhs.gov web site that any entity that is covered by the privacy act is required to give you a privacy practices notice (with certain exceptions).
If you didn't receive a privacy practices notice then the entity conducting the drug test is probably not covered by HIPAA. If you did receive a privacy practices notice then the entity conducting the test is covered by HIPAA and you have a right to review your records.
I am not aware of specific laws anywhere that automatically require such tests to be provided to the employee. This doesn't mean there aren't any; just that I don't know about them.
From a common law perspective, there are two contracts operating: the employee consents to the test as a prerequisite to the employment contract, and the contract between the employer and the testing organisation. Unless the former has something to say about the latter the employee has no rights under the latter contract.