Gestational age assessment in Nigerian newborn infants.

rate in terms of the amount of sweat produced and the virtual absence of failures. On the first day of life the average level of sweat sodium was decidedly higher than on the second and subsequent days, with an appreciable number of day 1 results exceeding the level of 70 mEq/1., generally accepted as the upper limit of normal. In one case the level was as high as 138 mEq/1. All 5 out of the 6 cases with high values on day 1, and which were available for retesting later, then gave normal levels well below 70 mEq/1. (Fig. 1). We conclude that a high sweat sodium (>70 mEq/1.) on day 1 is not necessarily indicative of CF, but from day 2 onwards it is much more likely to be so. Although the method is obviously not practicable as a routine screening procedure for CF, there are two circumstances when it is indicated. (1) Intestinal obstruction due to suspected meconium ileus, since if that diagnosis is confirmed by finding an abnormal sweat sodium level, conservative treatment with enemas may be appropriate; and (2) a previous sib has suffered from CF, with the 25% risk for subsequent offspring.