Simple quantitative HPLC method for measuring physiologic amino acids in cerebrospinal fluid without pretreatment.

The major goal of this study was to determine the effect of implementing the fFN test on hospital admission rates. We hypothesized that if clinicians were using a negative fFN result to rule out preterm labor, test implementation would lead to a decrease in admissions for preterm labor. One previous study showed reduced hospital admissions for preterm labor as a result of fFN testing by comparing admission rates before and after test introduction (5). Because of changes in our hospital's referral base in early 2002, we did not believe we could accurately assess the impact of fFN testing by comparing admission rates before and after test introduction. We therefore assessed the effect of implementing the fFN test as follows. We first compared the rate of hospital admission for Ͼ12 h for fFN-negative patients to the admission rate for fFN-positive patients. We found that fFN-negative patients were less likely to be admitted than fFN-positive patients (2% of fFN-negative patients vs 19% of fFN-positive patients were admitted; see Table 1C). This difference in admission rates was statistically significant (P ϭ 0.002). For the smaller subset of patients with survey results (n ϭ 58), the trend was similar although not statistically significant (2% vs 14%; P ϭ 0.14). These data suggest that clinicians are incorporating the fFN result in their decision making process. However, it is also possible that the differential admission rates reflect differences in the pre-test characteristics of fFN-negative and-positive patients, rather than the impact of test results on clinical management. To help distinguish between these possibilities, we examined the results of the pretest survey that accompanied each test requisition. We determined which patients had a high pretest probability of admission by noting whether the clinician circled " admit to observation " as a possibility on the pretest survey. If this option was circled, we counted the patient as " admission considered " (Table 1D). Although we cannot know the frequency with which these patients would have been admitted without the fFN result, we reasoned that clinicians' responses to this survey question should reflect any pretest differences between the fFN-positive and-negative patient populations. Overall, 57% of patients were considered for admission. Interestingly, the proportions of fFN-positive and-negative patients considered for admission were very similar (64% and 55%, respectively; P ϭ 0.56). This finding suggests that the fFN result itself, rather than a pretest characteristic of the two patient populations, was the …