[MT-L] Creatinine clearance rule
Theresa Keith
Hi all,
We are magic 5.67 and I am wondering what other facilities are doing for their creatinine clearance calculations to include ideal body weight. I have a rule I used however the issue we are running into if the patient is over 65 and the lab value of creatinine is less than 1, it is not rounding up. I have tried using other calculations but I am having issues with them. Any help would be much appreciated.
The equation I am comparing to is from Lexicomp.
CrCl[mL/min] = ((140 - Age[yr]) * (Weight[kg]CrCl[mL/min] / (SerumCreat[mg/dL] * 72))) * CrCl[mL/min]Sex
CRCLADJ
;THIS CALUCATES AN ESTIMATED CRCL BASED ON AN ADJUSTED BODY WEIGHT. NOTE,
; THIS HAS BEEN MODIFED FROM CRCL.ADJW (THE MESSAGE "UNABLE TO CAC.. HAS BEEN
;REMOVED. I LEFT IT IN THE RULE, BUT DID NOT REFERENCE IT. IN THE LINE UNDER
; THE MESSAGE, I REPLACED THE MESSAGE PROMPT WITH ""
IF{IF{[f rx last ver result]("CREAT")^SRCR_.=.;
[f pt sex]^SX_.=.;
[f pt oe ht cm]^HT_.=.;
[f pt oe wt kgs]^WT_.=.;
[f pt cur age]^AGE_.=.} " Unable to calculate Creatinine Clearance. "^X,
" "," ";
IF{SX="M" 50;45.5}^S,
IF{SX="M" 1;0.85}^F,
IF{SRCR<1.0 1.0^SRCR},
S+(2.3*((HT/2.54)-60)!0)^IBW_.=.,
IF{[f pt oe wt kgs]>1 IBW*1.3}^ADBW_.=.,
IF{[f pt oe wt kgs]<IBW [f pt oe wt kgs]^IBW_.=.},
IF{[f pt oe wt kgs]>ADBW ([f pt oe wt kgs]-IBW)^OW},
IF{OW'<0 (OW*0.4)^OWC_.=.},
IF{OW'<0 (OWC+IBW)^IBW_.=.},
140-AGE*IBW/(72*SRCR)*F}^CRCL.ADJW;
Then the second part is
IF{[f rx calc]("CRCLADJ")^CRCL_.=.;
("Creatinine Clearance = "_CRCL_" ml/min")^X,[f rx msg](X)};
Thanks
Theresa Keith
Systems Analyst III
[P] 317.802.2158
[F] 317.802.2438
OrthoIndy.com
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Ventura, Andrew
Hi Theresa,
We’re not magic, and this is our LAB calc, not a PHA rule/calc, but it’s probably quite close. We recently implemented this in LAB to get a reasonable CrCL to PHA CDP’s and header for dose range per renal function checking.
;Custom formulas for returning estimated CrCL automatically upon result
; of an SCr. Cockcroft-gault for adults with weight modifications per pharmacy
; Schwarts original for babies less than one year old, and Schwartz revised
; for children 1yo to age 18. Please see Andrew Ventura in Pharmacy/IT with
; any concerns.
; Cockcroft-Gault CrCl = (140-age) * (Wt in kg) * (0.85 if female) / (72 * Cr)
;
; Per Clinical Pharmacy Consensus, patients with no height or no weight should return
; no value at all, so pharmacy does a more thorough review of renal fxn. Same
; for patients < 60" tall.
;
; Note: Since we are using an IDMS traceable assay for SCR
; we can use this formula for kids 1-18, not the complex one:
; GFR = (0.413 * HTCM)/SCr
;
; Notes below apply to the code line below each comment.
; ------------------------
;filter out non numeric CRE values. Prevents some kinds of crashes.
CRE?0D^CRET,
;store the current age, height, weight, sex to variables,
[f pt cur age]^AGE,
[f pt oe wt kg]^WTKG,
[f pt oe ht cm]^HTCM,
[f pt sex]^SEX,
;Store K value factor for child age and sex.
IF{L(AGE,"D")'=L(AGE) 1^BABY},
IF{BABY=1 0.45}^KVAL,
;Store gender factors for formulas for CrCL and IBW.
IF{SEX="M" "1";"0.85"}^SCC,
IF{SEX="M" "50";"45.5"}^SIBW,
;If 65 or greater and CRET<1.0, assume 1.0, if <65 and CRET<0.8, assume 0.8
IF{(CRET<1.0)&(AGE'<65) "1";(CRET<0.8)&(AGE<65) "0.8";CRET}^CC,
;convert height to inches
HTCM/2.54^HTIN,
;calc IBW
SIBW+(2.3*(HTIN-60))^IBW,
;flag for if pt less than 60" tall
HTIN<60^AHT,
;flag for if pts weight is less than IBW
WTKG<IBW^AWT,
; check to see if patient is greater than 30% above IBW, if so, use Adj Wt form
IF{((WTKG/IBW)'<1.3) (IBW+(0.4*(WTKG-IBW)))^ADJWT},
;if the patient is not eligible for IBW,use actual,if adjwt exists, use it,
; otherwise use IBW
IF{AHT!AWT WTKG;ADJWT_.'=. ADJWT;IBW}^PTWT,
; If using adjusted weight, make result 4 decimals, otherwise make it 2.
; I think. Decimals in meditech are weird.
IF{ADJWT_.'=. 1.0000;1.000000}^LIM,
;Do the formula! Hooray!
((140-AGE):10D*PTWT:10D*SCC:10D)/(72*CC)^RES,
;if 1-<18 years old, use this formula instead:(revised schwartz)
((0.413*HTCM)/(CRET))^PEDSRES,
;do the original schwartz formula for babies < 1 yr old too
((KVAL*HTCM)/(CRET)):2D^BABYRES,
;don't result anything if the height or weight is missing or pt <18yo.
;the \F\V was added by lab, I believe to make it flow through the
;lab analyzers or interfaces.
IF{HTCM_.=. [f lres no prt];WTKG_.=. [f lres no prt];
(AGE<18)&(BABY=1) BABYRES;AGE<18 PEDSRES;
HTCM<152.4 [f lres no prt];
RES/LIM}_"\F\V";
I intended at one point to have the number of decimal places in the PHA header signify to the pharmacists if the formula used an adjusted weight for obese patients, but we hadn’t closed that loop as it was low priority.
Hope this helps!
Andrew Ventura, Pharm.D, MBA
Pharmacy Informaticist, Information Systems
Augusta Health, Fishersville VA
C/S 5.67pp6 à 5.67pp19
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