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Falsely Elevated Whole-Blood Tacrolimus Levels in a Kidney Transplant Patient
NKF 2012 Spring Clinical Meetings Abstracts
109 IMPACT OF eGFR FORMULAE ON PREVALENCE OF CKD IN RANDOM POPULATION SCREENING -THE TEXAS CKD STUDY Mohammed SHussain, Ronnie Orozco, John Moeller and Sharma Prabhakar. Department of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX. Purpose: Current knowledge of prevalence of CKD is based on sample studies from sources such as National Health and Nutrition Examination Surveys (NHANES). The true prevalence of CKD in general population is currently unknown.The aim of the present study was to estimate the prevalence of CKD in a representative population in a general community of West Texas and evaluate the impact of using two different formulae for eGFR on CKD prevalence. Methods: Subjects with ages over 21 were prospectively recruited using random digit dialing method from a large West Texas community with a representative ethnic and urban-rural population mix. Detailed demographic and medical information as well as body weight, blood pressure and family history was obtained. Samples of ur ine and blood were collected for estimation of GFR and microalbuminuria. CKD was diagnosed using K-DOQI staging guidelines and the impact of using MDRD . vs CKD-EPI formula was evaluated on the prevalence ok CKD in this general community cohort. Results: We have enrolled 1,606 subjects in the Texas CKD Study to date. Of them, 1,579 subjects completed the study which included 922 (57%) Whites and 566 Hispanics (35%) while Blacks comprised 105 (7%). About 25% of the subjects were above the age of 60 and 58% of total were women. Using the KDOQI criteria and MDRD equation CKD was present in 17.03% while the prevalence was 15.3% using the CKD EPI formula. With CKD – EPI formula some of the subjects diagnosed as stage 3a without MA using MDRD formula were excluded from CKD thereby decreasing those with CKD stage III. Conclusions: These observations indicate that 17.03% of the subjects in an unselected random populat ion screening had CKD by K-DOQI criteria using the MDRD formula. This rate of prevalence is much higher than what is currently known. Of these 58% were in stage III or worse CKD. Most subjects were unaware of the condition. Using CKD - EPI formula excluded some of the CKD diagnosisand thereby decreased the prevalence slightly, which however was not sta tistically significant .
110 FALSELY ELEVATED WHOLE-BLOOD TACROLIMUS LEVELS IN A KIDNEY TRANSPLANT PATIENT Nabeel Imam, Nour Khouzam, Usman Rahmat, Amir Rashidi, Michelle Zuccato, Chanigan Nilubol, Serban Dragoi Georgetown University Hospital, Washington, DC Tacrolimus is a widely used calcineurin inhibitor in maintenance immunosuppression after kidney transplant. Accurate measurement of tacrolimus blood level is critical. Antibody–conjugated magnetic immunoassay (AMIA) is a commonly used method for the measurement of tacrolimus. Few cases of falsely elevated whole-blood tacrolimus levels using AMIA method have been reported. A 68-year-old Caucasian female underwent a deceased donor kidney transplant for end stage kidney disease and was maintained on tacrolimus therapy. One year later, patient presented with vomiting and fatigue. On admission, tacrolimus blood level was 10.9 ng/mL using AMIA and immune function assay (IFA) was 5 ng/mL. A diagnosis of CMV gastritis and duodenitis was made and tacrolimus was held. A daily measurement of tacrolimus blood level did not show a drop below 8 ng/mL even after 10 days of stopping tacrolimus. Meanwhile, serum creatinine remained stable at 0.8 mg/dL and the IFA was improving. Other serology workup was within the normal range. Blood samples were sent for analysis using the gold standard Liquid chromatography coupled with mass spectrometry, which showed undetectable levels of tacrolimus. After restarting tacrolimus, blood levels were monitored using both methods. A discrepancy in the results was still noted. We conclude that when high tacrolimus levels are observed in transplant patients for no apparent reason when the AMIA method is used, these should be reassessed immediately using the LC/MS technique to rule out falsely elevated results before making unnecessary adjustments to the tacrolimus dose.
A42
111 ASSOCIATION OF URINARY SODIUM-TO-POTASSIUM RATIO WITH OBESITY AND TOTAL PERCENT BODY FAT Nishank Jain; Essam F. Elsayed; Abu Minhajuddin; S. Susan Hedayati; University of Texas Southwestern Medical Center at Dallas, Veterans Affairs North Texas Health Care system, Dallas, Texas Previous studies reported the association of dietary sodium (Na), but not potassium (K), with type 2 DM. One study investigating a similar association with obesity was limited to Venezuelan participants. We examined the association of dietary Na and potassium (K) intake (measured by first void morning urinary Na to K ratio, UNa/K) with increased BMI and total body percent fat (TBPF, measured by DEXA scan), independent of the presence of DM, in 3,303 participants of the population-based multi-ethnic Dallas Heart Study using linear regression. Of the cohort, 52% were African American, 17% Hispanic, 12% diabetic, and 36% hypertensive. Mean (SD) age, BMI, TBPF and UNa/K were 43 (10) years, 30 (7) kg/m2, 32 (10) % and 4.2 (2.8). In the unadjusted model, for each SD (3 units) increase in UNa/K, BMI increased by 0.6 kg/m2, 95% CI (0.3, 0.9), and TBPF increased by 0.6% (0.2, 1.0), p values <0.0001 and 0.003, respectively. This association remained significant even after adjusting for age, race, gender, Diabetes Mellitus, systolic and diastolic BP, with adjusted values of 0.4 kg/m2 (0.1, 0.6) for BMI and for 0.4% (0.2, 0.7) for TBPF. These finding suggests that high dietary Na and low K intake are associated with an increase in obesity as measured by BMI and TBPF, but independent of high BP and the presence of DM.
112 CREATININE EXCRETION RTAE ESTIMATION IN AFRICAN AMERICAN FORMAR KIDNEY DONORS Sunil Kumar Jain, John M Arthur, and Milos N Budisavljevic Charleston, SC, USA. Determination of completeness of urine collection is done by comparing an individual’s measured creatinine excretion rate (CER) with expected CER calcualted by various equations published in the literature. Current clinical practice of an expected CER of 15-25 mg/kg per day in men, and 10-20 mg/kg per day in women does not account for many variables and may not be accurate in some settings. Moreover there are no data in African American (AA) former kidney donors. Data were determined from a group of African American Donors at a regional acedemic medical center. A single 24 hour urine collection with total amount voided was recorded for each subject and urine creatinine was measured. CER was expressed in miligrams per day. Previously published equations were used for calculation of estimated CER. Pearson correlation coefficient was calculated.
There were a total of 33 AA living kidney donors ( 22 women & 11 men). The mean measured CER was 1714. 84 mg / day (SD 515.32). The mean estimated CER was 1522.44 mg / day (SD 336.84). The median body weight and age were 89.5 kg ( ranges 49.8 - 127) and 42 years (ranges 26 - 66) respectively. Pearson coefficeint was 0.6919. In summary none of the published formulas for estimated CER are relaible for estimating creatinine excetion rate in AA formor kidney donors.
Am J Kidney Dis. 2012;59(4):A1-A92
109 IMPACT OF eGFR FORMULAE ON PREVALENCE OF CKD IN RANDOM POPULATION SCREENING -THE TEXAS CKD STUDY Mohammed SHussain, Ronnie Orozco, John Moeller and Sharma Prabhakar. Department of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX. Purpose: Current knowledge of prevalence of CKD is based on sample studies from sources such as National Health and Nutrition Examination Surveys (NHANES). The true prevalence of CKD in general population is currently unknown.The aim of the present study was to estimate the prevalence of CKD in a representative population in a general community of West Texas and evaluate the impact of using two different formulae for eGFR on CKD prevalence. Methods: Subjects with ages over 21 were prospectively recruited using random digit dialing method from a large West Texas community with a representative ethnic and urban-rural population mix. Detailed demographic and medical information as well as body weight, blood pressure and family history was obtained. Samples of ur ine and blood were collected for estimation of GFR and microalbuminuria. CKD was diagnosed using K-DOQI staging guidelines and the impact of using MDRD . vs CKD-EPI formula was evaluated on the prevalence ok CKD in this general community cohort. Results: We have enrolled 1,606 subjects in the Texas CKD Study to date. Of them, 1,579 subjects completed the study which included 922 (57%) Whites and 566 Hispanics (35%) while Blacks comprised 105 (7%). About 25% of the subjects were above the age of 60 and 58% of total were women. Using the KDOQI criteria and MDRD equation CKD was present in 17.03% while the prevalence was 15.3% using the CKD EPI formula. With CKD – EPI formula some of the subjects diagnosed as stage 3a without MA using MDRD formula were excluded from CKD thereby decreasing those with CKD stage III. Conclusions: These observations indicate that 17.03% of the subjects in an unselected random populat ion screening had CKD by K-DOQI criteria using the MDRD formula. This rate of prevalence is much higher than what is currently known. Of these 58% were in stage III or worse CKD. Most subjects were unaware of the condition. Using CKD - EPI formula excluded some of the CKD diagnosisand thereby decreased the prevalence slightly, which however was not sta tistically significant .
110 FALSELY ELEVATED WHOLE-BLOOD TACROLIMUS LEVELS IN A KIDNEY TRANSPLANT PATIENT Nabeel Imam, Nour Khouzam, Usman Rahmat, Amir Rashidi, Michelle Zuccato, Chanigan Nilubol, Serban Dragoi Georgetown University Hospital, Washington, DC Tacrolimus is a widely used calcineurin inhibitor in maintenance immunosuppression after kidney transplant. Accurate measurement of tacrolimus blood level is critical. Antibody–conjugated magnetic immunoassay (AMIA) is a commonly used method for the measurement of tacrolimus. Few cases of falsely elevated whole-blood tacrolimus levels using AMIA method have been reported. A 68-year-old Caucasian female underwent a deceased donor kidney transplant for end stage kidney disease and was maintained on tacrolimus therapy. One year later, patient presented with vomiting and fatigue. On admission, tacrolimus blood level was 10.9 ng/mL using AMIA and immune function assay (IFA) was 5 ng/mL. A diagnosis of CMV gastritis and duodenitis was made and tacrolimus was held. A daily measurement of tacrolimus blood level did not show a drop below 8 ng/mL even after 10 days of stopping tacrolimus. Meanwhile, serum creatinine remained stable at 0.8 mg/dL and the IFA was improving. Other serology workup was within the normal range. Blood samples were sent for analysis using the gold standard Liquid chromatography coupled with mass spectrometry, which showed undetectable levels of tacrolimus. After restarting tacrolimus, blood levels were monitored using both methods. A discrepancy in the results was still noted. We conclude that when high tacrolimus levels are observed in transplant patients for no apparent reason when the AMIA method is used, these should be reassessed immediately using the LC/MS technique to rule out falsely elevated results before making unnecessary adjustments to the tacrolimus dose.
A42
111 ASSOCIATION OF URINARY SODIUM-TO-POTASSIUM RATIO WITH OBESITY AND TOTAL PERCENT BODY FAT Nishank Jain; Essam F. Elsayed; Abu Minhajuddin; S. Susan Hedayati; University of Texas Southwestern Medical Center at Dallas, Veterans Affairs North Texas Health Care system, Dallas, Texas Previous studies reported the association of dietary sodium (Na), but not potassium (K), with type 2 DM. One study investigating a similar association with obesity was limited to Venezuelan participants. We examined the association of dietary Na and potassium (K) intake (measured by first void morning urinary Na to K ratio, UNa/K) with increased BMI and total body percent fat (TBPF, measured by DEXA scan), independent of the presence of DM, in 3,303 participants of the population-based multi-ethnic Dallas Heart Study using linear regression. Of the cohort, 52% were African American, 17% Hispanic, 12% diabetic, and 36% hypertensive. Mean (SD) age, BMI, TBPF and UNa/K were 43 (10) years, 30 (7) kg/m2, 32 (10) % and 4.2 (2.8). In the unadjusted model, for each SD (3 units) increase in UNa/K, BMI increased by 0.6 kg/m2, 95% CI (0.3, 0.9), and TBPF increased by 0.6% (0.2, 1.0), p values <0.0001 and 0.003, respectively. This association remained significant even after adjusting for age, race, gender, Diabetes Mellitus, systolic and diastolic BP, with adjusted values of 0.4 kg/m2 (0.1, 0.6) for BMI and for 0.4% (0.2, 0.7) for TBPF. These finding suggests that high dietary Na and low K intake are associated with an increase in obesity as measured by BMI and TBPF, but independent of high BP and the presence of DM.
112 CREATININE EXCRETION RTAE ESTIMATION IN AFRICAN AMERICAN FORMAR KIDNEY DONORS Sunil Kumar Jain, John M Arthur, and Milos N Budisavljevic Charleston, SC, USA. Determination of completeness of urine collection is done by comparing an individual’s measured creatinine excretion rate (CER) with expected CER calcualted by various equations published in the literature. Current clinical practice of an expected CER of 15-25 mg/kg per day in men, and 10-20 mg/kg per day in women does not account for many variables and may not be accurate in some settings. Moreover there are no data in African American (AA) former kidney donors. Data were determined from a group of African American Donors at a regional acedemic medical center. A single 24 hour urine collection with total amount voided was recorded for each subject and urine creatinine was measured. CER was expressed in miligrams per day. Previously published equations were used for calculation of estimated CER. Pearson correlation coefficient was calculated.
There were a total of 33 AA living kidney donors ( 22 women & 11 men). The mean measured CER was 1714. 84 mg / day (SD 515.32). The mean estimated CER was 1522.44 mg / day (SD 336.84). The median body weight and age were 89.5 kg ( ranges 49.8 - 127) and 42 years (ranges 26 - 66) respectively. Pearson coefficeint was 0.6919. In summary none of the published formulas for estimated CER are relaible for estimating creatinine excetion rate in AA formor kidney donors.
Am J Kidney Dis. 2012;59(4):A1-A92