Multiple Myeloma: Likelihood Ratios

Introduction: Multiple myeloma is a plasma cell neoplasm producing a large amount of an immunoglobulin (IgG) causing end-organ damage. In particular, the patient must meet the following 3 criteria:

Presence of a monoclonal protein in the serum and/or urine

Presence of monoclonal plasma cells in the bone marrow >10%

Presence of end-organ damage: hypercalcemia, renal insufficiency, anemia, or lytic bone lesions

Diagnosis of a monoclonal proteinopathy proceeds with SPEP, UPEP, free light chains (FLC).

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Tags: Hematologic Neoplasm Tag this Diagnosis.

The likelihood ratios of findings for Multiple Myeloma are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Good Positive and Negative Likelihood Ratios
Finding	Result	+LR	-LR
[ + ] SPEP and FLC	+ 0 -	100	0
Study: Ann Clin Lab Sci. 2006 Spring;36(2):157-62. PMID: 16682511
[ + ] Serum Free Light Chains	+ 0 -	44	0.1
Patients with k/l ratios >1.65 or <0.26 are identified as producing clonal {kappa} or {lambda} FLCs, respectively. Study: Ann Clin Lab Sci. 2006 Spring;36(2):157-62. PMID: 16682511
[ + ] SPEP	+ 0 -	3.4	0.4
aka Serum Protein Electrophoresis The presence of one or more distinct peaks not corresponding to the usual protein bands in the gamma or beta globulin regions indicated the possible presence of a monoclonal or polyclonal gammopathy. Study: Ann Clin Lab Sci. 2006 Spring;36(2):157-62. PMID: 16682511

Poorly Diagnostic Findings
Finding	Result	+LR	-LR
[ + ] Serum Immunofixation Electrophoresis		Sensitivity = 93%
specificity not assessed. For patients defined by abnormal urine immunofixation electrophoresis. Study: Mayo Clin Proc. 2006 Dec;81(12):1575-8. PMID: 17165636
[ + ] Proteinuria		Sensitivity = 88%
specificity not assessed Study: Mayo Clin Proc. 1975 Jan;50(1):29-40. PMID: 1110582
[ + ] X-Ray		Sensitivity = 79%
specificity not assessed Study: Mayo Clin Proc. 1975 Jan;50(1):29-40. PMID: 1110582
[ + ] UPEP		Sensitivity = 75%
globulin spike specificity not assessed Study: Mayo Clin Proc. 1975 Jan;50(1):29-40. PMID: 1110582
[ + ] Renal Insufficiency		Sensitivity = 55%
specificity not assessed Study: Mayo Clin Proc. 1975 Jan;50(1):29-40. PMID: 1110582
[ + ] Bence-Jones Proteinuria		Sensitivity = 49%
monoclonal light chains in urine specificity not assessed Study: Mayo Clin Proc. 1975 Jan;50(1):29-40. PMID: 1110582
[ + ] Hypercalcemia		Sensitivity = 30%
specificity not assessed Study: Mayo Clin Proc. 1975 Jan;50(1):29-40. PMID: 1110582
[ + ] Palpable Liver		Sensitivity = 21%
specificity not assessed Study: Mayo Clin Proc. 1975 Jan;50(1):29-40. PMID: 1110582
[ + ] Hypogammaglobulinemia		Sensitivity = 9%
specificity not assessed Study: Mayo Clin Proc. 1975 Jan;50(1):29-40. PMID: 1110582
[ + ] Palpable Spleen		Sensitivity = 5%
specificity not assessed Study: Mayo Clin Proc. 1975 Jan;50(1):29-40. PMID: 1110582