No, an employer may accept a negative/dilute test result as a negative test. If the employer wants a retest it may do so, however, it must be stated in the employer's policy and the employer must require a retest of all individuals that have a negative/dilute result in the same testing category.
Alcohol affects activity of such neurotransmitters as glutamate, GABA, and dopamine; caffeine blocks the action of the neurotransmitter adenosine. Such changes are studied in the field of psychopharamacology, which concerns the effects of drugs on the mind and brain. This field investigates both recreational drugs such as alcohol, caffeine, marijuana, cocaine, and LSD, and therapeutic drugs such as antidepressants and antipsychotics.
Brain Chemical Imbalances after Long-Term Alcohol Use. Alcohol has widespread effects on the brain and can affect neurons (nerve cells), brain chemistry, and blood flow within the frontal lobes of the brain. Neurotransmitters (chemical messengers in the brain) are affected by long-term use of alcohol. When a person who is dependent on alcohol stops drinking, chemical responses create an overexcited nervous system and agitation by changing the level of chemicals that inhibit impulsivity or stress and excitation.