BUN and Creatinine prior to CAT scan

Specialties Radiology


Does anyone routinely get a BUN and Creatinine prior to CT scaning?Who orders them? How does the department get the results? What is the cut off for to scan or not to scan? Who do you hydrate? Who do you use mucomyst on? How soon before the scan do you get the blood work? Can the bloodwork be, say, a month old? I am trying to write a protocol for this and make the referring physician responsible for it. I would have no problem having the results sent to me and logging them for CT and setting up a short stay bed for hydration. Oh, another question, How much fluid do you hydrate them with?Any help would be appriciated. Thanks in advance....

Anne Patterson RN, CRN


567 Posts

All of my experience in this arena is related to trauma. To begin with, we usually order a full set of labs on every admit we get. Then we subsequently order any additional tests, radiology included.

CT will call us if we order a CT with contrast and ask us for the values of the BUN and CRT, I unfortunately do not know what their cut off is, but I am usually reluctant to give contrast to patients with CRT > 2. This includes PO and IV contrast.

Usually we will do an ultrasound to assess a belly when the patient has a high CRT, or if the picture apears to warrant it, the patient will go straight to surgery for an ex-lap. Otherwise most of our patients can wait to be rehydrated in the ICU and get the scan later. We usually base our fluid replacement on the value of the base deficit on the ABG.

Hope that helped.


566 Posts

Specializes in ER, Hospice, CCU, PCU.

At our hospital the CT Techs will only inject contrast if they have the Bun and Creat results. If the Doctors need an ultra-stat CT Scan to be done prior to lab results being back (Ie:trauma/head bleed) the ER Doc has to go and inject the patient themselves.

Sorry that's as much as I know about CT Scans and Lab results. (I don't think they had CT scanners when I was in school LOL)


18 Posts

At our hospital, we fill out a precontrast questionnaire. If a patient has any impaired renal function, or renal disease, or one kidney, or if they are receiving the medication - metphormine(glucaphage) then we need a creatinine. This is picked up while doing the screening form. Our booking office will also alert us if a patient is diabetic, then it is the RN's responsibility to phone the patient and see if they are taking metphormine, then we arrange to have the patient go for bloodwork and the results are faxed to our Diagnostic Imaging Dept.. The creatinine has to be within 3 months. If it hasn't been done within the last 3 months, we do it stat. We do not have any protocol for rehydrating the patient. :cool: I hope this answers some of your questions.

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