Per- and polyfluoroalkyl substances (PFAS), man-made chemicals with highly fluorinated carbon chains, are used in many commercial applications. Trace levels of several long-chain PFAS, including perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), have been detected in the blood of almost every American, while short-chain PFAS are seldom detected. These findings may reflect lower exposure to short-chain PFAS or that, in humans, short-chain PFAS eliminate efficiently in urine. Because of changes in manufacturing of long-chain PFAS, short-chain PFAS and fluorinated alternatives, including perfluoroalkyl ether carboxylic acids (e.g., GenX, ADONA), are increasingly used. Moreover, detection of PFAS and fluorinated alternatives in drinking water has raised concerns about potential implications to human health from exposure through contaminated water. We developed an analytical method adequate for large biomonitoring programs like the National Health and Nutrition Examination Survey (NHANES), and report concentrations of 15 C3-C11 PFAS, GenX, and ADONA in urine and serum collected in 2016 from a convenience sample of 50 American residents with no known exposure to these chemicals. In serum, we did not detect GenX or ADONA; detection frequency and concentration patterns of other PFAS agreed with those from NHANES. In urine, we did not detect fluorinated alternatives, and rather infrequently short-chain PFAS (e.g., perfluorobutanoate in 56% of samples, median=0.2 µg/L; 95th percentile=0.6 µg/L). Despite widespread presence in serum, long-chain PFAS in urine were non-detectable (<0.1 µg/L). These results suggest limited exposure to both short-chain PFAS and select fluorinated alternatives in this convenience population, and stress the relevance of selecting the correct biomonitoring matrix to characterize exposure. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the CDC.