Tests may include CBC (complete blood count), thyroid function tests, serum calcium, serum potassium, etc.Abdominal X-rays are generally only performed if bowel obstruction is suspected, may reveal extensive impacted fecal matter in the colon, and may confirm or rule out other causes of similar symptoms.Colonoscopy may be performed if an abnormality in the colon like a tumor is suspected. Other tests rarely ordered include anorectal manometry, anal sphincter electromyography, and defecography.Colonic propagating pressure wave sequences (PSs) are responsible for discrete movements of the bowel contents and are vital for normal defecation. Deficiencies in PS frequency, amplitude, and extent of propagation are all implicated in severe defecatory dysfunction (SDD). Mechanisms that can normalize these aberrant motor patterns may help rectify the problem. Recently the novel therapy of sacral nerve stimulation (SNS) has been utilized for the treatment of severe constipation. Criteria
The Rome III Criteria for functional constipation must include two or more of the following and present for the past three months, with symptoms starting for at least 6 months prior to diagnosis. Straining during defecation for at least 25% of bowel movements
Lumpy or hard stools in at least 25% of defecations
Sensation of incomplete evacuation for at least 25% of defecations
Sensation of anorectal obstruction/blockage for at least 25% of defecations
Manual maneuvers to facilitate at least 25% of defecations
Fewer than 3 defecations per week
Loose stools are rarely present without the use of laxatives
There are insufficient criteria for irritable bowel syndrome

Prevention
Constipation is usually easier to prevent than to treat.
Pronounced protective effect in animal poisoning with arsenic and mercury was first shown by I. Okonishnikova in 1962. In 1984, the now-defunct Bock Pharmaceutical Company requested the FDA grant approval for orphan drug status under the brand name Chemet and the FDA approved of this in 1991, providing exclusivity until 1998 which was conveyed to the successor Sanofi in 1996. References
Further reading
Aposhian, H.V. ; Aposhian, M.M. (1990). "Meso-2,3-dimercaptosuccinic acid: Chemical, pharmacological and toxicological properties of an orally effective metal chelating agent". Annual Review of Pharmacology and Toxicology. 30 (1): 279–306. doi:10.1146/annurev.pa.30.040190.001431. PMID 2160791. External links
"Succimer". Drug Information Portal. U.S. National Library of Medicine.