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deoxyuridine suppression test (dUST)

Indications: - folate deficiency - vitamin B12 deficiency (perhaps indirectly) Principle: the test uses radiolabel & requires bone marrow aspiration dUMP is converted to dTMP by thymidilate synthase, an enzyme that uses N5,N10-methylenetetrahydrofolate as a cofactor. The test measures the impaired ability of deoxyuridine to suppress incorporaton of tritiated thymidine into DNA of cultured bone marrow cells. thymidylate DNA synthase pol dUMP -----------> thymidine + thymidine* ----> DNA * The test based upon competition of unlabeled thymidine synthesized from dUMP with added tritiated thymidine. It measures thymidylate synthase activity which uses N5,N10-methylenetetrahydrofolate as a cofactor. Addition of cobalamin or various folates to culture may help sort out the deficiency.

Related

deoxyuridine folic acid; folate; vitamin B9 N5,N10-methylenetetrahydrofolate thymidylate synthase; TS; TSase (TYMS, TS, OK/SW-cl29) vitamin B12; cobalamin

General

special chemistry test

References

  1. Smith, R. Jewish Home for the Aging, Reseda CA, unpublished manuscript 2001
  2. Carmel R, Ann Rev Med 51:357, 2000
  3. Killman SA, Acta Med Scand 175:483, 1964
  4. Metz et al, Br J Haematol 14:575, 1968