Path Biol. 232 (9): 233–252. Diagnosis
The diagnostic workup of a suspected iodine deficiency includes signs and symptoms as well as possible risk factors mentioned above. A 24-hour urine iodine collection is a useful medical test, as approximately 90% of ingested iodine is excreted in the urine. For the standardized 24-hour test, a 50 mg iodine load is given first, and 90% of this load is expected to be recovered in the urine of the following 24 hours. Recovery of less than 90% is taken to mean high retention, that is, iodine deficiency. The recovery may, however, be well less than 90% during pregnancy, and an intake of goitrogens can alter the test results.If a 24-hour urine collection is not practical, a random urine iodine-to-creatinine ratio can alternatively be used. However, the 24-hour test is found to be more reliable.A general idea of whether a deficiency exists can be determined through a functional iodine test in the form of an iodine skin test. In this test, the skin is painted with an iodine solution: if the iodine patch disappears quickly, this is taken as a sign of iodine deficiency. However, no accepted norms exist on the expected time interval for the patch to disappear, and in persons with dark skin color the disappearance of the patch may be difficult to assess. If a urine test is taken shortly after, the results may be altered due to the iodine absorbed previously in a skin test.
Yemen
In Yemen the Sayyids are more generally known as sadah; they are also referred to as Hashemites. In terms of religious practice they are Shia, Sunni, and Sufi. Sayyid families in Yemen include the Rassids, the Qasimids, the Mutawakkilites, the Hamideddins, some Al-Zaidi of Marib, Sanaa, and Sadah, the Ba Alawi sada families in Hadhramaut, Mufadhal of Sanaa, Al-Shammam of Sadah, the Sufyan of Juban, and the Al-Jaylani of Juban. Libya
The Sayyids in Libya are Sunni, including the former royal family, which is originally Zaidi-Moroccan (also known as the Senussi family). The El-Barassa Family are Ashraf as claimed by the sons of Abdulsalam ben Meshish, a descendant of Hassan bin Ali bin Abi Talib. South Asia
Although people in South Asia claim Hashemite descent, genealogy family trees are studied to authenticate claims. In 1901 the total number of Sayyids in British India was counted as 1,339,734. History of South Asian Sayyids
Sayyids migrated many centuries ago from different parts of the Middle East and Central Asia (Turkestan) during the invasion of the Mongols, Ghaznavid dynasty, Delhi Sultanate, and Mughal Empire, encompassing a timespan of roughly until the late 19th century. Sayyids migrated to Sindh, Uch, Bihar Sharif, Sheikhpura ,  and Attock Khurd (Punjab) and settled there very early. Other early migrant Sayyids moved deep into the south to the Deccan sultanates located in the Deccan Plateau region in the time of the Bahmani Sultanate, and later Golkonda, Nizam Shahi of Ahmednagar, Bijapur, Bidar, and Berar.