In Reply.—We appreciate the comments of Dr Chantler and his colleagues. It is unlikely that the differences in mean triglyceride (TG) levels observed in the two studies are due to differences in biochemical methods. We measured TG by the Hantzch condensation colorimetric method; in contrast, the London group measured TG levels using a fluorometric method. We compared the two methods with the aid of Regional Quality Control Pool 652 of Hyland Scan Service. For a given specimen, a cumulative mean of 112.0 mg/100 ml (coefficient of variation, 5.6) was obtained with the colorimetric method compared with 116.1 mg/100 ml (coefficient of variation, 11.8) with the fluorometric method.
Our patients were dialyzed for 18 hr/wk compared with 30 hours in the London study; mean predialysis serum creatinine level after a 65-hour interdialytic period was 8.9 ± 1.8 mg/100 ml. From the data available, it is difficult to compare the