Hans L. Willems

Introduction of the CKD-EPI equation to estimate glomerular filtration rate in a Caucasian population

BACKGROUNDnChronic kidney disease (CKD) is defined as the presence of kidney damage, albuminuria or a reduction in glomerular filtration rate (GFR). A GFR <60 mL/min/1.73 m(2) alone is sufficient to diagnose CKD Stages III-V. Recently, the new chronic kidney disease epidemiology collaboration (CKD-EPI) equation was introduced. It has been suggested to result in higher estimated glomerular filtration rates (eGFRs) than the Modification of Diet in Renal Disease (MDRD(4)) formula. Here, we assess consequences of introducing the CKD-EPI equation in a West European Caucasian population.nnnMETHODSnData were obtained from 6097 Caucasian participants of the Nijmegen Biomedical Study (2823 males and 3274 females). Serum creatinine values were determined using the Jaffe method, calibrated against mass spectrometry and were used to calculate eGFR(MDRD4) and eGFR(CKD-EPI). Demographic data, health status and information on medication use for all participants was obtained with a postal questionnaire.nnnRESULTSnThe introduction of the CKD-EPI equation changed the curve of eGFR by age, with higher values in the younger age groups and a steeper decline of eGFR with ageing. As a consequence, younger people were more often classified to a higher GFR stage and older people, especially males, to a lower GFR stage.nnnCONCLUSIONSnIn comparison with the MDRD(4) formula, the CKD-EPI equation leads to higher estimates of GFR in young people and lower estimates in the elderly. On a population level, this may lead to higher estimates of kidney function. However, in routine clinical practice where the population is predominantly elderly, the opposite may be true. The introduction of eGFR(CKD-EPI) necessitates reconsidering the definition of CKD. We suggest introducing age-dependent threshold values and/or the use of urinary albumin excretion to improve risk stratification.

Beta-2-microglobulin is superior to N-acetyl-beta-glucosaminidase in predicting prognosis in idiopathic membranous nephropathy

BACKGROUNDnAn accurate prediction of prognosis in patients with idiopathic membranous nephropathy (iMN) would allow restriction of immunosuppressive treatment to patients who are at highest risk for end-stage renal disease (ESRD). Several markers of proximal tubular cell injury have been used as predictors of prognosis. In this study we compared the accuracy of urinary beta-2-microglobulin (U beta 2m) and N-acetyl-beta-glucosaminidase (U beta-NAG) in predicting renal insufficiency and remission rates.nnnMETHODSnFifty-seven patients with iMN (38 M, 19 F; age 48 +/- 16 years), a nephrotic syndrome and a serum creatinine level <135 micromol/l were studied prospectively. At baseline, a standardised measurement was carried out to determine renal function and protein excretion. The end-point renal failure was defined as a serum creatinine exceeding 135 micromol/l or an increase in serum creatinine by >50%. Remission was defined as a proteinuria <2.0 g/day with stable renal function.nnnRESULTSnThe mean follow-up was 80 +/- 36 months. The mean serum creatinine concentration was 89 +/- 20 micromol/l, serum albumin 24 +/- 5.3 g/l and proteinuria 8.9 +/- 4.8 g/24 h. Thus far, 28 (49%) patients have reached the predefined end point of renal failure. Multivariate analysis identified U beta 2m as the strongest independent predictor for the development of renal insufficiency. Sensitivity and specificity were 81 and 90% respectively for U beta 2m (threshold value 54 microg/mmol cr), and 74 and 81% respectively for U beta-NAG (threshold value 2.64 U/mmol cr). The overall remission rate was 44%. A remission occurred in 78% of patients with low U beta 2m and in 14% of patients with high U beta 2m, and respectively in 71% of patients with low U beta-NAG and 21% of patients with high U beta-NAG.nnnCONCLUSIONSnAlthough both U beta 2m and U beta-NAG predicted progression and remission in iMN, U beta 2m was more accurate. High specificity in predicting prognosis should be pursued to avoid unnecessary immunosuppressive therapy. We therefore conclude that U beta 2m is superior to U beta-NAG in predicting prognosis in patients with iMN.

Does the band cell survive the 21st century

Abstract:u2002 Objectives:u2002The differentiation of white blood cells is a worldwide‐accepted method to obtain medical information. The conventional microscopic differential, however, is a laborious and expensive test with a low statistical value. Especially for band cell identification there is a wide range of variance. In this report we describe the intervariability of band cell enumeration. Methods:u2002From a septic patient, an EDTA anti‐coagulated blood sample was obtained and a smear was made and stained (May‐Grünwald Giemsa). A PowerPoint presentation was made twice of 100 random cells and sent to 157 different hospital laboratories in the Netherlands for a leukocyte differential. In the first survey neutrophils were differentiated in segmented and band neutrophils whereas in the second survey no discrimination was made between segmented and band neutrophils. Results:u2002The first survey was responded by 68% of the laboratories (756 individuals) and the second survey by 73% of the laboratories (637 individuals). The laboratory mean values of the segmented neutrophils were 42.9% (SD: 7.8, range 22–64%) and 69.9% (SD: 1.4, range 62–72%) for the first and second survey respectively. For the individual technicians the values of the segmented neutrophils were 43.9% (SD: 11.2, range 15–72%) and 70.0% (SD: 2.0, range 59–77%) for the first and second survey respectively. Conclusions:u2002Because of the enormous variation of band cell counting we recommend to cease quantitative reporting of band cells, especially since the results only have a clinical relevance in a limited number of pathological circumstances.

The divergent morphological classification of variant lymphocytes in blood smears

An examination of a blood smear may be requested by physicians or initiated by laboratory staff as a diagnostic aid when a lymphoproliferative disorder or mononucleosis is suspected.1 The classification of lymphocyte disorders is complex because there are various manifestations of these disorders.2,3 Three major groups can be distinguished: reactive lymphocytosis, premalignant neoplastic disorders of lymphocytes and neoplastic disorders of lymphocytes.4 Lymphocyte disorders may be accompanied by abnormal lymphocyte morphology; therefore it is important to recognise and report abnormal lymphocytes, such as atypical lymphocytes and lymphoblasts. The ability of individual technicians, however, to recognise abnormal lymphocytes is consistently quite poor.5 There are no standardised definitions regarding the morphology of the various cells, and interpretation is based on individual experience and dependent on the availability of additional clinical information. Often, transitional forms between lymphocytes and plasma cells are seen in the blood of patients with viral infections. These cells are variously known as atypical lymphocytes, lymphocytoid plasma cells or plasmacytoid lymphocytes.6 The so-called atypical lymphocyte is a non-neoplastic lymphocyte seen in the peripheral blood, and appears to be a non-specific response to stress from a variety of disorders.7 Small lymphocytes become larger in size and become capable of dividing. These atypical lymphocytes …