a change in diet by lowering their triglyceride level below 120 mg dl their risk of encountering an obstructed catheter would drop by over 90 percent the use of triglyceride as a criteria will produce a false positive less than six percent of the time the high degree of accuracy in predicting which patients are likely to encounter an obstructed catheter and the low risk of a false positive makes triglyceride level an excellent criteria for the method of the present invention referring next to fig2 b the bar demonstrates the effectiveness of the method of the present invention in using measured cholesterol level as a criteria for preventing patients who have an implanted pump and catheter from experiencing clogging or obstruction of the catheter it may be seen that of the patients who have a cholesterol level of 215 mg dl or below over 92 percent will not develop a clogged catheter as predicted by the use of cholesterol level as a sole criteria by using a cholesterol level of 210 mg dl or below as the criteria over 90 percent will not develop a clogged catheter as shown by the dotted line in fig2 b this 90 to 92 percent level is felt to represent an acceptable degree of risk patients above the 200 to 215 mg dl level would be strongly encouraged to lower their cholesterol level below 200 mg dl this may be accomplished by a change in diet by lowering their cholesterol level below 200 mg dl their risk of encountering an obstructed catheter would drop by nearly 80 percent the use of cholesterol as a criteria will produce a false positive less than six percent of the time at the 215 mg dl level and approximately 22 percent of the time at the.