How does the MDRD Study equation compare with serum creatinine in routine healthcare? Anatomy of MDRD-eGFR.

The Modification of Diet in Renal Disease Study equation-estimated glomerular filtration rate (MDRD-eGFR) as a marker for chronic kidney disease, with a single decision level for both genders and all adult ages, requires that the calculated quantity is independent of gender and age. In a retrospective study of S-Creatinine concentrations from laboratory information systems of hospitals in the UK and Sweden, comprising about 140,000 results in total, it was found that the MDRD-eGFR indeed differs between genders and that it varies with age more than the S-Creatinine concentration does. If the age compensation is deleted from the algorithm, the relative changes in the MDRD-eGFR decrease and become almost the same as those for S-Creatinine concentrations. The difference between the genders could probably be overcome by increasing the "if female factor". We used Pt-Iohexol and S-Creatinine concentrations measured simultaneously to estimate the performance of the MDRD-eGFR in relation to Pt-Iohexol clearance. The Pt-Iohexol varies considerably between patients with the same S-Creatinine concentrations, a difference that is not reflected in the MDRD-eGFR. It is concluded that the mathematical transformation of S-Creatinine concentrations does not add any diagnostic value. On the contrary, an increased measurement uncertainty is unavoidable with the use of factors and exponents. The uncertainty is greater than any difference between age and gender in adjacent age groups. There is no compensation for the individual relation between S-Creatinine and Iohexol clearance, and the equation does not consider the individual body surface area; it is therefore inadvisable to use the MDRD-eGFR values as the basis for administration of drugs excreted by the kidneys.

Design of a bio-mathematical prediction model using serum tumor markers and immunohistochemistry in peritoneal carcinomatosis with ovarian involvement: a pilot study.

The diagnosis of disseminated intra-abdominal malignancy in women with ovarian involvement can be problematic. Whilst both blood tumor markers and use of immunohistochemical staining on tissue can help decide the origin of the tumor, this is done separately. This study looked at the blood and tissue marker profiles of 198 cases of disseminated malignancy to construct a model, which may help to determine tumor origin. The original histology material from 198 cases of disseminated intra-abdominal epithelial malignancy were reviewed, blind, and reassessed as to the likely site of origin. These cases had immunohistochemical (IHC) staining for cytokeratins (CK) 7 and 20, carcinoembryonic antigen (CEA) and CA125. Blood values for CEA and CA125 were also known at diagnosis. The histologic types of the tumors in this pilot study were of ovarian type morphologically in 130 cases (65.7%), nonovarian in 32 (16.1%), and not assigned in 36 cases (18.2%). The majority of the nonovarian cases were of mucinous type or too poorly differentiated to classify. Analysis showed an overall sensitivity and specificity of 93% and 69%, and positive predictive and negative predictive value of 92% and 71%, respectively, for a diagnosis of ovarian vs nonovarian origin using histology alone vs histology and IHC. Use of an ordinal regression developed a model which uses tissue staining for CK 7 and CEA along with blood levels of CEA to help determine the site of tumor origin.

Applicability of estimated glomerular filtration rate in stratifying chronic kidney disease.

OBJECTIVE: The aim of this audit was to evaluate the degree of glomerular filtration rate (GFR) among inpatients and outpatients in a District General Hospital, with special attention given to laboratory testing and impact on health delivery. BACKGROUND: UK Chronic Kidney Disease guidelines recommend that investigation of renal function should be accompanied by an estimation of GFR (eGFR) in order to identify and manage patients with chronic kidney disease (CKD). The estimated GFR forms the basis for classification of CKD and appropriate action plans for patient management and follow-up. METHOD: A retrospective audit of 8160 results from a predominantly British Caucasian population was carried out; extracting creatinine results from two isolated months in years 2001 and 2004. The estimated GFR (eGFR) was calculated using the MDRD formula. The data were classified according to demography, serum creatinine and eGFR. Patients from the 2001 database were classified according to eGFR and those with a value of <60 mL/min/1.73 m(2) were followed up in 2004. RESULTS: The difference in eGFR between the men and women was significantly different with medians (confidence intervals) of 80.1 (41-109) and 64.4 (30-84.6) (p<0.0001), respectively. There was an inverse association between age and eGFR in both genders (p<0.0001), with a decrease in eGFR of around 7 % for each decade increase in age. 1926 patients (24 %) of results studied had eGFR <60 mL/min, of whom 64 % were females and 36 % males. Follow-up of patients with eGFR<60 mL/min from 2001 showed that 4 % progressed to stages 4 and 5 CKD. CONCLUSION: eGFR is inversely associated with increasing age and female gender. MDRD derived eGFR fails to completely compensate for age and gender variations and thus different action limits may be required. Small but significant numbers of patients progressed to stages 4 and 5 CKD. Additional clarity in describing "progressive fall in eGFR" in the guidelines would improve identification of the population most at risk.

Screening for microalbuminuria by use of microproteinuria.

We aimed to develop a reliable, low cost method to assess the early stages of renal impairment in diabetes, for use in high-risk populations in countries with limited resources. We evaluated a trichloroacetic acid (TCA) turbidimetric method for microproteinuria screening in patients with diabetes. The method was compared with an immunoturbidimetric procedure for the detection of microalbumuniuria. Both methods performed within limits of allowable uncertainty based on inter- and intra-individual variation. A urinary albumin/creatinine ratio of 3.0 g/mol, assumed as diagnostic of microalbuminuria, was found to correlate with a cut-off value of 24 mg/L for microproteinuria. The clinical sensitivity and specificity of the TCA method determined against this ratio were 86% and 90% respectively. The reliability and practicability of the TCA method renders it suitable for the detection of early stage renal damage, with emphasis on screening high-risk populations in countries with limited resources.

Screening for microalbuminuria by use of microproteinuria

We aimed to develop a reliable, low cost method to assess the early stages of renal impairment in diabetes, for use in high-risk populations in countries with limited resources. We evaluated a trichloroacetic acid [TCA] turbidimetric method for microproteinuria screening in patients with diabetes. The method was compared with an immunoturbidimetric procedure for the detection of microalbumuniuria. Both methods performed within limits of allowable uncertainty based on inter- and intra-individual variation. A urinary albumin/creatinine ratio of 3.0 g/mol, assumed as diagnostic of microalbuminuria, was found to correlate with a cut-off value of 24 mg/L for microproteinuria. The clinical sensitivity and specificity of the TCA method determined against this ratio were 86% and 90% respectively. The reliability and practicability of the TCA method renders it suitable for the detection of early stage renal damage, with emphasis on screening high-risk populations in countries with limited resources