Calculated globulin as a screening tool for hypogammaglobulinaemia or paraproteins in hospitalized patients.

BACKGROUND: Calculated globulin fraction is derived from the liver function tests by subtracting albumin from the total protein. Since immunoglobulins comprise the largest component of the serum globulin concentration, increased or decreased calculated globulins and may identify patients with hypogammaglobulinaemia or hypergammaglobulinaemia, respectively. METHODS: A retrospective study of laboratory data over 2.5 years from inpatients at three tertiary hospitals was performed. Patients with paired calculated globulins and immunoglobulin results were identified and clinical details reviewed. The results of serum electrophoresis testing were also assessed where available. RESULTS: A total of 4035 patients had paired laboratory data available. A calculated globulin ≤20 g/L (<2nd percentile) had a low sensitivity (5.8%) but good positive predictive value (82.5%) for hypogammaglobulinaemia (IgG ≤5.7 g/L), with a positive predictive value of 37.5% for severe hypogammaglobulinaemia (IgG ≤3 g/L). Paraproteins were identified in 123/291 (42.3%) of patients with increased calculated globulins (≥42 g/L) who also had a serum electrophoresis performed. Significantly elevated calculated globulin ≥50 g/L (>4th percentile) were seen in patients with either liver disease (37%), haematological malignancy (36%), autoimmune disease (13%) or infections (9%). CONCLUSIONS: Calculated globulin is an inexpensive and easily available test that assists in the identification of hypogammaglobulinaemia or hypergammaglobulinaemia which may prompt further investigation and reduce diagnostic delays.

Systemic Atherosclerotic Inflammation Following Acute Myocardial Infarction: Myocardial Infarction Begets Myocardial Infarction.

BACKGROUND: Preclinical data suggest that an acute inflammatory response following myocardial infarction (MI) accelerates systemic atherosclerosis. Using combined positron emission and computed tomography, we investigated whether this phenomenon occurs in humans. METHODS AND RESULTS: Overall, 40 patients with MI and 40 with stable angina underwent thoracic 18F-fluorodeoxyglucose combined positron emission and computed tomography scan. Radiotracer uptake was measured in aortic atheroma and nonvascular tissue (paraspinal muscle). In 1003 patients enrolled in the Global Registry of Acute Coronary Events, we assessed whether infarct size predicted early (≤30 days) and late (>30 days) recurrent coronary events. Compared with patients with stable angina, patients with MI had higher aortic 18F-fluorodeoxyglucose uptake (tissue-to-background ratio 2.15±0.30 versus 1.84±0.18, P<0.0001) and plasma C-reactive protein concentrations (6.50 [2.00 to 12.75] versus 2.00 [0.50 to 4.00] mg/dL, P=0.0005) despite having similar aortic (P=0.12) and less coronary (P=0.006) atherosclerotic burden and similar paraspinal muscular 18F-fluorodeoxyglucose uptake (P=0.52). Patients with ST-segment elevation MI had larger infarcts (peak plasma troponin 32 300 [10 200 to >50 000] versus 3800 [1000 to 9200] ng/L, P<0.0001) and greater aortic 18F-fluorodeoxyglucose uptake (2.24±0.32 versus 2.02±0.21, P=0.03) than those with non-ST-segment elevation MI. Peak plasma troponin concentrations correlated with aortic 18F-fluorodeoxyglucose uptake (r=0.43, P=0.01) and, on multivariate analysis, independently predicted early (tertile 3 versus tertile 1: relative risk 4.40 [95% CI 1.90 to 10.19], P=0.001), but not late, recurrent MI. CONCLUSIONS: The presence and extent of MI is associated with increased aortic atherosclerotic inflammation and early recurrent MI. This finding supports the hypothesis that acute MI exacerbates systemic atherosclerotic inflammation and remote plaque destabilization: MI begets MI. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01749254.