Basic Concepts in Clinical Biochemistry-A Practical Guide.7z

To Determine the Uric Acid Concentration

in Serum and Urine^20

20.1 Theory

Uric acid is the end product of purine metabolism (adenine and guanine) present in
RNA and DNA. Uric acid is 2,6,8-trihydroxypurine and exists in keto and enol
forms. It exists only as the monosodium and disodium salt. In plasma, uric acid is
present as monosodium salt. The pool of uric acid in the body is about 1200 mg, out
of which about half amount undergoes turnover daily, that is, about 600 mg/dl is
formed daily and about the same amount is lost, of which about 75% is exerted
through urine and about 25% destroyed by bacteria in the colon.

N

N

Enol form Keto form

N N

H

N N N

H HH

OH

OH

O

O

O

HN

HO

Structure of uric acid

20.2 Specimen Requirements

Serum is stable for 3–5 days at 4C and for 6 months at 20 C. Do not use oxalate
for phosphotungstate method. For uricase method, do not use EDTA orfluoride. For
urine sample, collect 24 h sample. Do not refrigerate and add NaOH to keep urine
alkaline.

#Springer Nature Singapore Pte Ltd. 2018
V. Kumar, K. D. Gill,Basic Concepts in Clinical Biochemistry: A Practical Guide,
https://doi.org/10.1007/978-981-10-8186-6_20

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