Diagnosing empty iron stores in women: unbound iron binding capacity (UIBC) versus soluble transferrin receptor (sTFR).

Unbound iron binding capacity (UIBC) is more accurate than total iron binding capacity (TIBC) and percent transferrin saturation in diagnosing empty iron stores. It is unknown whether UIBC is more or less accurate than soluble transferrin receptor (sTFR). We obtained public-use data from the U.S. National Health and Nutrition Examination Survey (NHANES) 2005-2006 to compare the accuray of UIBC and sTFR in diagnosing empty iron stores in 2337 women aged 12-49 years. We grouped the women according to CRP less than 5 mg/L and pregnancy (four groups) and used three definitions of empty iron stores: Serum ferritin less than 10, 15, and 20 µg/L. Receiver operating characteristic (ROC) curve analysis was used to estimate the diagnostic accuracy. UIBC showed a better diagnostic accuracy than sTFR in all groups and definitions of empty iron stores, except in nonpregnant women with CRP at least 5 mg/L when empty iron stores were defined as ferritin less than 10 and 15 µg/L. Two differences reached statistical significance: In nonpregnant women without inflammation the area under the ROC curve for UIBC was 0.830 compared to 0.793 for sTFR (p = .007) when empty iron stores were defined as ferritin less than 20 µg/L. The corresponding figures for pregnant women without inflammation were 0.843 for UIBC and 0.739 for sTFR (p = .003). In conclusion, UIBC is a more accurate test than sTFR in diagnosing empty iron stores in women without inflammation.

Lower hemoglobin with lower ferritin - results from the HUNT 2 Study.

AIM: We wanted to study the association between blood hemoglobin concentration (b-hemoglobin) and serum ferritin concentration (s-ferritin) in a healthy female population, and compare the findings to those in a previous study of ambulant female patients. METHODS: We compared median b-hemoglobin and the fraction with anemia in groups of women with s-ferritin from less than 10 µg/L to 100 µg/L. These women, aged 20-55 years, were part of a health screening survey (HUNT 2) where they reported to have 'good' or 'very good' general health and were found to have normal s-creatinine. The s-ferritin values were adjusted to the level of the previous study. The 10, 50 and 90 percentiles of b-hemoglobin were modelled as functions of s-ferritin using quantile regression. RESULTS: Among 2122 healthy females the entire b-hemoglobin distribution was shifted downwards in women with s-ferritin less than 20 µg/L. Accordingly, the median b-hemoglobin was statistically significantly lower. In women with s-ferritin less than 20 µg/L the fraction with anemia was 0.15. CONCLUSIONS: Lower s-ferritin is associated with lower b-hemoglobin in many more subjects than those labelled anemic.

Inhibition of platelet receptors involved in neutrophil-platelet interaction in model cardiopulmonary bypass.

We investigated the interactions between neutrophils, platelets, and artificial surfaces, and whether blocking of relevant receptors on platelets reduced unwanted activation responses in model cardiopulmonary bypass. Isolated neutrophils and platelets resuspended in heparin-anticoagulated plasma were recirculated with and without blocking antibodies to CD62P, CD42b, or junctional adhesion molecule C (JAM-C) in polyvinyl chloride tubing using a roller pump. Platelet adhesion to the tubing was inhibited by anti-CD42b and anti-CD62P, and adhesion of neutrophils by anti-JAM-C. Formation of platelet-neutrophil and platelet aggregates was reduced by anti-CD62P. Anti-JAM-C decreased platelet-neutrophil aggregation at low concentrations and platelet macroaggregates at high concentrations. Anti-CD62P increased neutrophil CD11b expression but not degranulation. Anti-JAM-C substantially increased neutrophil degranulation and slightly increased CD11b expression. Platelet activation increased when CD62P was blocked and decreased with anti-CD42b antibody. High-dose anti-JAM-C reduced platelet activation. In conclusion, inhibiting platelet and neutrophil-platelet interactions had useful effects but no single blocking antibody seemed capable of inducing only beneficial effects.

Activation of neutrophil granulocytes in an in vitro model of a cardiopulmonary bypass.

Activated neutrophils play a central role in the pathogenesis of postoperative organ dysfunction after surgery with cardiopulmonary bypass. The researchers used an in vitro roller pump model to investigate the relative importance of the biomaterial, platelets, plasma proteins including activated complement, and flow mode on neutrophil activation as shown by the adhesion, degranulation, and increased the surface expression of CD11b. Neutrophil adhesion to the biomaterial increased with platelet addition, but not with plasma. Biomaterial contact activated neutrophils in a serum-free buffer, but was significantly increased by activated complement. Platelets increased neutrophil degranulation in a serum-free buffer but tended to reduce it in plasma. CD11b expression increased in both media. Complement activation was higher with neutrophils alone than with neutrophils and platelets combined. The roller pump reduced neutrophil adhesion and increased degranulation compared to passive rotation. Neutrophil interaction with platelets and complement were more important for activation than biomaterial contact and use of the roller pump. Improvement of biocompatibility is dependent on modifying complement activation and platelet interaction with neutrophils.