Straight Cath vs Clean Catch UA: Bad Data Is Worse Than No Data!

After eight years of hospitalist medicine and seeing inaccurate urinalysis results day after day, year after year, I've come to the conclusion that the straight cath vs clean catch debate is not a debate.  If the urine didn't come from a straight cath, I have faith issues in the accuracy of the results.    I know, I know, it takes time and effort for a nurse to perform the straight cath.  It's not comfortable for the patient to have a catheter inserted into their urethra.  Plus, with bad nursing technique, one could introduce bacteria into the bladder when performing a straight cath urinalysis.

All that aside, if I'm a physician trying to make medical decisions based on accurate data, then having bad urine results that don't represent the true picture is worse than not having any data at all.  For example, here's a classic case of trying to make medical decisions based on bad data.  Below is a snap shot of three UA results obtained from an  ER over two visits.  I'm sure it's the same no matter where you get your care in this country.  The first two urinalysis results came from a clean catch sample of a horribly weak 89 year old female who presented with family complaints of "fever and weakness" two days in a row.  


There are several issues going on here.
  1. The patient  got sent home from the ER on Day #1 with a diagnosis of UTI based on a contaminated clean catch UA.  The final culture returned three days later as a verified contaminated sample with greater than three organisms present.  That means the sample was too dirty to be interpreted with any accuracy.
  2. I was asked to admit the patient on Day #2 for "weakness and fever" after the patient  presented to the ER for the second time in less than 24 hours.
  3. I asked that the third urinalysis be performed in the ER as a straight cath sample after eight years of knowledge that clean catch urinalysis is about as accurate as diagnosing a pulmonary embolism on a chest xray.
Ultimately, I showed that this patient did not have a UTI but rather a DVT.  I have had many moans and groans over the years from nurses questioning why I need a straight cath urinalysis on combative 45 year old schizophrenics we are asked to see with "abnormal UA" or the confused 84 year old with dementia dropping F bombs every other sentence.    From now until eternity, if I ever have a nurse question why they can't just do a clean catch vs a straight cath, I'm going to refer them here, to my nonrandomized, highly scientific N=1 case presentation here at The Happy Hospitalist.  Hospitalists are internists.  That means paying attention to the details is what we do.  Too many epithelial cells on a UA and you can bet there's a chance it may be a bad collection sample.  In many ways, this is worse than no sample collection at all.  This ecard snark helps explain:

"If there are more than 50 epithelial cells on a 'clean catch' UA, you might as well culture the innter thigh instead."


Some of this post contains humor that may only be understood by some healthcare providers. Read at your own risk.

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