Resetting the detection level of cord blood thyroid stimulating hormone (TSH) for the diagnosis of congenital hypothyroidism.

An appraisal of a 17-year primary thyroid stimulating hormone (TSH) screening programme for the detection of congenital hypothyroidism was carried out to establish the reference interval of cord blood TSH in unaffected infants; the mean cord blood TSH concentration of affected infants and the incidence of congenital hypothyroidism in the Najran province of Saudi Arabia. Our findings show a reference interval of cord blood TSH of 2.0-16.8 mU/l in unaffected infants; a mean cord blood TSH concentration of 399 mU/l in affected infants; a false positive rate for the diagnosis of at-risk infants of 1.02% and a congenital hypothyroidism incidence rate of 34/100 000 (1 : 2931) live births. These findings suggest that there is a need to reset the cord blood TSH concentration for the detection of at-risk infants. We suggest that the detection level of cord blood TSH for the recognition of at-risk infants can be set at 90 mU/l rather than the recommended level of 30 mU/l. This should reduce the false positive rate for detection of infants at risk of congenital hypothyroidism.

Serum cholinesterase activity helps to distinguish between liver disease and non-liver disease aberration in liver function tests.

The diagnostic usefulness of a single determination of serum cholinesterase activity to distinguish between overt liver disease and non-liver disease clinical problems in which a few of the traditional liver function tests are abnormal was assessed. Using three groups of subjects comprising liver disease, non-liver disease, and healthy controls, we have shown that serum cholinesterase activity helped to distinguish between liver disease and non-liver disease in subjects who had abnormality of a few liver function tests. Serum cholinesterase activity helped also to distinguish between the liver disease subjects and healthy controls. There was no statistically significant difference between the mean serum cholinesterase activities of non-liver disease subjects and healthy controls. We suggest that determination of serum cholinesterase activity is a cost-effective diagnostic means of differentiating between overt liver disease and non-liver diseases where there may be aberration of some liver function tests.