The risk of a multiple myeloma in patients with paraproteinemia:a myeloma risk score developed in the region of the Comprehensive Cancer Center West

Diagnoses in patients with paraproteinaemia are diverse; few (mostly single centre based) studies are known that describe incidence, diagnoses and follow-up in patients with paraproteinaemia. In the region of the Comprehensive Cancer Centre West in the Netherlands (population 1.6 million, 1992) a population-based registry was set up in the period 1991-1993. Patients (n = 1464; median age: 72 years; range: 16-102) were entered by clinical chemists, internists, haematologists, and pathologists. Multiple myeloma and plasmacytoma were diagnosed in 261 patients (18%), paraprotein-related haematological diseases in 159 patients (11%) and paraprotein-related internal diseases in 210 patients (14%). After bone marrow examination monoclonal gammopathy of unknown significance (MGUS) was diagnosed in 207 (14%) patients. No further diagnosis could be made in 627 (43%) patients mostly for lack of supplementary bone marrow and (or) X-ray examinations. Consequently, more than two-thirds of all patients with a newly found paraprotein did not show any sign of a haematological malignancy. Using these data a 'myeloma risk score' was developed to predict the presence of a multiple myeloma based on paraprotein type and concentration, aiding the physician in determining which patients should undergo further bone marrow and skeletal examinations.</p

Development of a "Myeloma Risk Score" using a population-based registry on paraproteinemia and myeloma

Diagnostic systems for monoclonal gammopathies use bone marrow and X-ray examinations to exclude multiple myeloma (MM). Data from a population-based registry of unselected patients with paraproteinemia indicate that these tests are often done only when MM is suspected. We used 441 randomly selected patients to develop a simple four point "Myeloma Risk Score" based on two readily available laboratory tests. One point was given for paraprotein concentration > or = 10 g/l, one point for IgG and IgA, and two points for IgD and light chains only. A score of 0 or 1 indicated a low risk for MM, with scores of 2 and 3 signifying high risks. Sensitivity, specificity, positive and negative predictive value (PV) for the Myeloma Risk Score in the training sample were 92%, 88%, 79%, and 96% respectively. Extrapolating these results to a larger cohort showed that 90% of patients with a monoclonal gammopathy could be classified correctly as having MM or a non-myeloma condition. The Myeloma Risk Score can identify patients with a paraproteinemia at risk for MM, and who are therefore candidates for bone marrow and X-ray examination

De kans op de ziekte van Kahler (multipel myeloom) bij patiënten met een paraproteïnemie: myeloomrisicoscore, ontwikkeld in de regio van het Integraal Kankercentrum West

Diagnoses in patients with paraproteinaemia are diverse; few (mostly single centre based) studies are known that describe incidence, diagnoses and follow-up in patients with paraproteinaemia. In the region of the Comprehensive Cancer Centre West in the Netherlands (population 1.6 million, 1992) a population-based registry was set up in the period 1991-1993. Patients (n = 1464; median age: 72 years; range: 16-102) were entered by clinical chemists, internists, haematologists, and pathologists. Multiple myeloma and plasmacytoma were diagnosed in 261 patients (18%), paraprotein-related haematological diseases in 159 patients (11%) and paraprotein-related internal diseases in 210 patients (14%). After bone marrow examination monoclonal gammopathy of unknown significance (MGUS) was diagnosed in 207 (14%) patients. No further diagnosis could be made in 627 (43%) patients mostly for lack of supplementary bone marrow and (or) X-ray examinations. Consequently, more than two-thirds of all patients with a newly found paraprotein did not show any sign of a haematological malignancy. Using these data a 'myeloma risk score' was developed to predict the presence of a multiple myeloma based on paraprotein type and concentration, aiding the physician in determining which patients should undergo further bone marrow and skeletal examinations

Comparison of single and dual-platform assay formats for CD34+ haematopoietic progenitor cell enumeration

Most techniques for CD34+ cell enumeration are dual platform assays. That is, they derive absolute numbers of CD34+ cells from either the flow cytometrically assessed per cent (%) CD34+ cells within the nucleated cells and/or the white blood cell count from a haematology cell analyser. Recently, so-called single-platform assays have been developed, in which the absolute number of CD34+ cells is directly derived from a single flow cytometric measurement. The present study aims to compare the variation between eight laboratories in CD34+ cell counts from paired assays of 15 samples using a common single (ProCOUNT) and the local dual-platform method. Six laboratories used the 'SIHON' and two the 'ISHAGE' protocol for CD34+ cell enumeration. Use of the single-platform method reduced the inter-laboratory variation in per cent and absolute numbers of CD34+ cells, as measured by interquartile ranges, by half but did not lead to an appreciable reduction of the inter-laboratory variation in white blood cell counts. Thus, part of the reduced inter-laboratory variation obtained with ProCOUNT may have been a result of the use of standardized procedures and reagents to detect CD34+ cells. In order to eliminate any variation arising from the use of different local protocols for percentage of CD34+ cell assessments, a comparison was made of the ProCOUNT-derived absolute CD34+ cell numbers (i.e. single platform) with the dual-platform absolute CD34+ cell numbers calculated by multiplying ProCOUNT-derived percentage of CD34+ cells and with the corresponding haematology analyser-derived white blood cell count. Regardless, the interquartile ranges of absolute CD34+ cell numbers remained almost a factor of two smaller with the use of the single platform method. Thus, these results suggest that single-platform methodology can reduce the variation in absolute CD34+ cell numbers between laboratorie