Presence Of Hemoglobin Research Articles

Device for Quantification of Bilirubin in Cerebral Spinal Fluid

In North America, an estimated 30,000 patients annually experience an aneurysmal subarachnoid hemorrhage (SAH). In approximately five percent of these patients, the hemorrhage is not visible on computerized tomography scans due to the inability to image blood at time intervals greater than 12 h post symptom onset. For these patients (many of which have experienced a sentinel hemorrhage that is a precursor to a more significant rupture), a method is needed for accurately analyzing cerebral spinal fluid (CSF) for evidence of SAH. Further, it is necessary to differentiate blood associated with the SAH from blood associated with the spinal tap procedure. This letter presents a point-of-care device that is capable of performing such an analysis. The stand-alone prototype device uses commercially available embedded system components to implement a point-of-care device that is capable of collecting and analyzing optical absorbance spectra. A mathematical model for the hemorrhagic CSF sample is then developed by using a partial-least-squares-regression-based regression methodology that is able to differentiate between SAH and blood associated with the spinal tap. This differentiation is achieved by quantifying bilirubin (associated with the breakdown of old blood) in the CSF. Initial testing on the prototype device suggests that the device is able to quantify bilirubin in the presence of hemoglobin over concentrations ranges that are clinically relevant to the patient population of interest.

Environmental survey to assess viral contamination of air and surfaces in hospital settings

SummaryThe presence of pathogenic viruses in healthcare settings represents a serious risk for both staff and patients. Direct viral detection in the environment poses significant technical problems and the indirect indicators currently in use suffer from serious limitations. The aim of this study was to monitor surfaces and air in hospital settings to reveal the presence of hepatitis C virus, human adenovirus, norovirus, human rotavirus and torque teno virus by nucleic acid assays, in parallel with measurements of total bacterial count and haemoglobin presence. In total, 114 surface and 62 air samples were collected. Bacterial contamination was very low (<1 cfu/cm2) on surfaces, whereas the ‘medium’ detected value in air was 282 cfu/m3. Overall, 19 (16.7%) surface samples tested positive for viral nucleic acids: one for norovirus, one for human adenovirus and 17 (14.9%) for torque teno virus (TTV). Only this latter virus was directly detected in 10 air samples (16.1%). Haemoglobin was found on two surfaces. No relationship was found between viral, biochemical or bacterial indicators. The data obtained confirm the difficulty of assessing viral contamination using bacterial indicators. The frequent detection of TTV suggests its possible use as an indicator for general viral contamination of the environment.

A Highly Fluorescent Hydrophilic Ionic Liquid as a Potential Probe for the Sensing of Biomacromolecules

With respect to the conventional imidazolium ionic liquids which generally create very weak fluorescence with quantum yields at extremely low levels of 0.005-0.02, a symmetrical hydrophilic ionic liquid 1,3-butylimidazolium chloride (BBimCl) was found to be highly fluorescent with λ(em) at 388 nm when excited at λ(ex) < 340 nm. The very high quantum yield of BBimCl in aqueous medium, derived to be 0.523 when excited at 315 nm, was attributed to its symmetrical plane conjugating structure. In the presence of hemoglobin, the fluorescence of BBimCl could be significantly quenched, resulting from the coordinating interaction between the iron atom in the heme group of hemoglobin and the cationic imidazolium moiety. This feature of the present hydrophilic ionic liquid makes it a promising fluorescence probe candidate for the sensitive sensing of hemoglobin. A linear regression was observed within 3 × 10(-7) to 5 × 10(-6) mol L(-1) for hemoglobin, and a detection limit of 7.3 × 10(-8) mol L(-1) was derived.

Quantitative analysis of Hb Bart’s in cord blood by capillary electrophoresis system

It has long been recognized that the presence of hemoglobin (Hb) Bart's in newborn's blood is associated with α-thalassemia. However, the automated high-performance liquid chromatography or low-performance liquid chromatography system is unable to quantify the amount of Hbs Bart's and H, which are eluted at the retention time close to 0min. This study used automatic capillary electrophoresis (CE) system to diagnose various types of α-thalassemia in 587 cord blood samples, including 429 normal α-globin genotype, 120 cases of thalassemia with one α-globin gene defect, 34 cases with two α-globin genes defect, and four cases with three α-globin genes defect. The result showed that the level of Hb Bart's in cord blood was increased accordingly with the increasing numbers of the defective α-globin genes. In addition, Hb Bart's level at 0.2%, as measured by CE, can be used as a cut-off point for α-thalassemia diagnosis in newborns.

NONINVASIVE DIAGNOSIS OF ULCERATIVE COLITIS ON THE BASIS OF FECAL LACTOFERRIN AND IMMUNOCHEMICAL HEMOCCULT TEST

The aim of the study was to assess the possibility of diagnosing ulcerative colitis on the basis of complex comparative analysis of diagnostic significance of clinical signs of the disease which are symptoms of anxiety, C-reactive protein, erythrocyte sedimentation rate, immunochemical hemoccult test and fecal lactoferrin. 52 patients with ulcerative colitis, 46 patients with irritable bowel syndrome and 25 healthy volunteers were examined. The level of lactoferrin was detected in samples of feces taken from one defecation act by immunosorbent assay (ELISA) using kits ELISA TEST KIT Hycult Biotechnology (Netherlands). The concentration of the marker at the level of 15,25 mg / g was defined as a separation point. The presence of hemoglobin in feces was detected using immunochemical hemoccult test with sets of the firm «Biotech Atlantic, Inc.» (U.S.). The erythrocyte sedimentation rate and C-reactive protein were determined by means of conventional methods. The fecal lactoferrin (0,895 ± 0,0315) and immunochemical hemoccult test (0,825 ± 0,0397) showed the highest diagnostic significance in the diagnosis of ulcerative colitis. They are ahead of traditional laboratory markers: ESR (p < 0,0001) and p = 0,0075, respectively) and CRP ((p = 0,0004 and p = 0,0083, respectively). The sensitivity of fecal lactoferrin made up 80,77 % (95 % CI: 67,50-90,40), specificity - 90,14 % (95 % CI: 80,70-95,90), immunochemical hemoccult test - 69,23 % (95 % CI: 54,90-81,30) and 95,77 % (95 % CI: 88,10-99,10), respectively. Consequently, the fecal lactoferrin and immunochemical hemoccult test were sensitive and specific markers in the diagnosis of ulcerative colitis.

Effect of hemoglobin on the NO-donor ability of μ2-S-bis(pyrimidine-2-thiolato)tetranitrosyldiiron

The hydrolysis of the iron nitrosyl complex [Fe2(μ2-SC4H3N2)2(NO)4](C4H3N2S− is pyrimidine-2-thiolate) in the presence of hemoglobin (Hb) is accompanied by the NO release into a solution. In the absence of Hb, the starting complex is oxidized by nitric oxide that is released into a solution, which leads to further transformations of NO, nitric oxide being present in the solution only partially. The effective rate constant for the decomposition of the complex is high and depends on its concentration. On the one hand, in the presence of Hb, NO molecules rapidly and irreversibly bind to Hb to form HbNO, which is the intermediate in the nitric oxide metabolism. On the other hand, the reversible binding of the iron nitrosyl complex to the surface functional groups of Hb leads to a decrease in its concentration in a solution and deceleration of the formation of NO. Therefore, Hb can ensure the complete and more prolonged assimilation of NO.

DIFFERENTIAL DIAGNOSIS OF ORGANIC AND FUNCTIONAL PATHOLOGY BOWELS ON THE BASIS OF FECAL LACTOFERRIN AND IMMUNOCHEMICAL HEMOCCULT TEST

The aim of the study was to assess the possibility of differential diagnosis of organic and functional bowels pathology in the comprehensive comparative analysis of the diagnostic value of clinical signs before the symptoms of anxiety, ESR, and immunochemical tests for fecal occult blood and fecal lactoferrin. 90 patients with organic pathology of intestines (42 patients with active ulcerative colitis and 48 patients with colorectal cancer) and 46 patients with irritable bowel syndrome have been examined. Lactoferrin was detected in stool samples taken from one defecation act, enzyme immunoassay (ELISA) using kits ELISA TEST KIT Hycult Biotechnology (Netherlands). The concentration of the marker at the level of 15,25 mg/g was defined with point of separation. The presence of hemoglobin in the feces was determined using immunochemical test for occult blood in the stool sets firm «Biotech Atlantic, Inc.» (U.S.). Fecal lactoferrin (0,931 ± 0,021) and immunochemical tests for fecal occult blood (0,922 ± 0,0224) showed the highest diagnostic utility in the differential diagnosis of organic and functional pathology of the intestines. They are ahead of the symptoms of anxiety (p = 0,002 and p = 0,005 respectively) and erythrocyte sedimentation rate (p < 0,001 and p = 0,001 respectively). The sensitivity of fecal lactoferrin was 85.56 % (95 % CI: 70,80-87,30), specificity - 84,78 % (95 % CI: 71,10-93,60), immunochemical test for occult blood in feces - 84,44 % (95 % CI: 75,30-91,20) and 100,00 % (95 % CI: 92,20-100,00), respectively. Consequently, fecal lactoferrin and immunochemical hemoccult test were sensitive and specific markers in the differential diagnosis of organic and functional pathology of the intestines.

A detailed spectroscopic study on the interaction of Rhodamine 6G with human hemoglobin

UV–vis, time-resolved fluorescence and circular dichroism spectroscopic investigations have been made to reveal the nature of the interactions between xanthene dye Rhodamine 6G and the well known protein hemoglobin. From the analysis of the steady-state and time-resolved fluorescence quenching of Rhodamine 6G in aqueous solutions in presence of hemoglobin, it is revealed that the quenching is static in nature. The primary binding pattern between Rhodamine and hemoglobin has been interpreted as combined effect of hydrophobic association and electrostatic interaction. The binding constants, number of binding sites and thermodynamic parameters at various pH of the environment have been computed. The binding average distance between the energy donor Rhodamine and acceptor hemoglobin has been determined from the Forster’s theory.

Protein molecularly imprinted polyacrylamide membrane: for hemoglobin sensing

A hemoglobin sensor based on a molecularly imprinted polymer-modified electrode has been fabricated by electrochemically induced redox polymerization of acrylamide in the presence of hemoglobin.

IlsA, A Unique Surface Protein of Bacillus cereus Required for Iron Acquisition from Heme, Hemoglobin and Ferritin

The human opportunistic pathogen Bacillus cereus belongs to the B. cereus group that includes bacteria with a broad host spectrum. The ability of these bacteria to colonize diverse hosts is reliant on the presence of adaptation factors. Previously, an IVET strategy led to the identification of a novel B. cereus protein (IlsA, Iron-regulated leucine rich surface protein), which is specifically expressed in the insect host or under iron restrictive conditions in vitro. Here, we show that IlsA is localized on the surface of B. cereus and hence has the potential to interact with host proteins. We report that B. cereus uses hemoglobin, heme and ferritin, but not transferrin and lactoferrin. In addition, affinity tests revealed that IlsA interacts with both hemoglobin and ferritin. Furthermore, IlsA directly binds heme probably through the NEAT domain. Inactivation of ilsA drastically decreases the ability of B. cereus to grow in the presence of hemoglobin, heme and ferritin, indicating that IlsA is essential for iron acquisition from these iron sources. In addition, the ilsA mutant displays a reduction in growth and virulence in an insect model. Hence, our results indicate that IlsA is a key factor within a new iron acquisition system, playing an important role in the general virulence strategy adapted by B. cereus to colonize susceptible hosts.

Effect of HbS in the determination of HbA2 with the Menarini HA‐8160 analyzer and comparison with other instruments

It is known that the presence of hemoglobin S (HbS) affects the determination of hemoglobin A(2) (HbA(2)) levels in clinical samples. We quantitated this effect using the Menarini HA-8160 analyzer and compared with other instruments (HELENA beta-thal quik column, TOSOH HLC-723G7 and BIORAD Variant II) using the HELENA SAS-MX alkaline gel electrophoresis kit as the reference method. The %HbA(2) values from the HA-8160 analyzer and the alkaline gel electrophoresis show a good linear correlation in the absence of HbS. A strong positive bias in the %HbA(2) values from the HA-8160 is apparent in the presence of HbS in the samples, when compared with the alkaline electrophoresis. The analytical imprecision and bias of the three HPLC instruments are comparable both in the presence and absence of HbS. The manual column method shows a lower bias in the absence of HbS but is more affected when HbS is present in the samples.

Obtaining Blood Samples From Peripheral Intravenous Catheters: Best Practice?

Obtaining Blood Samples From Peripheral Intravenous Catheters: Best Practice?

Nitric Oxide-Loaded Echogenic Liposomes for Nitric Oxide Delivery and Inhibition of Intimal Hyperplasia

We sought to develop a new bioactive gas-delivery method by the use of echogenic liposomes (ELIP) as the gas carrier. Nitric oxide (NO) is a bioactive gas with potent therapeutic effects. The bioavailability of NO by systemic delivery is low with potential systemic effects. Liposomes containing phospholipids and cholesterol were prepared by the use of a new method, freezing under pressure. The encapsulation and release profile of NO from NO-containing ELIP (NO-ELIP) or a mixture of NO/argon (NO/Ar-ELIP) was studied. The uptake of NO from NO-ELIP by cultured vascular smooth muscle cells (VSMCs) both in the absence and presence of hemoglobin was determined. The effect of NO-ELIP delivery to attenuate intimal hyperplasia in a balloon-injured artery was determined. Coencapsulation of NO with Ar enabled us to adjust the amount of encapsulated NO. A total of 10 microl of gas can be encapsulated into 1 mg of liposomes. The release profile of NO from NO-ELIP demonstrated an initial rapid release followed by a slower release during the course of 8 h. Sixty-eight percent of cells remained viable when incubated with 80 microg/ml of NO/Ar-ELIP for 4 h. The delivery agent of NO to VSMCs by the use of NO/Ar-ELIP was 7-fold greater than unencapsulated NO. We discovered that NO/Ar-ELIP remained an effective delivery agent of NO to VSMCs even in the presence of hemoglobin. Local NO-ELIP administration to balloon-injured carotid arteries attenuated the development of intimal hyperplasia and reduced arterial wall thickening by 41 +/- 9%. Liposomes can protect and deliver a bioactive gas to target tissues with the potential for both visualization of gas delivery and controlled therapeutic gas release.

Electrochemical Impedance Spectroscopy and Cyclic Voltammetry on Ferritin in the Presence of Hemoglobin

Electrochemical and interfacial behavior of ferritin-immobilized gold electrode in the presence of hemoglobin was investigated using electrochemical impedance spectroscopy and cyclic voltammetry. Working electrode used in this study was a gold disk electrode on which ferritin was immobilized by holding at −0.5 V for 3 mins. Hemoglobin added in phosphate buffer caused the interfacial impedance of the ferritin immobilized gold electrode to decrease significantly. Based on the impedance data, ferric ion reduction at 0.0 V vs. Ag/AgCl and hydrogen evolution reaction at −0.8 V vs. Ag/AgCl appeared to be enhanced by hemoglobin in phosphate buffer. This result indicated that hemoglobin-added electrolyte could modify the ferritin layer immobilized on gold electrode and caused reduction of charge transfer resistance on the ferritin related reactions.

A Review of Variant Hemoglobins Interfering with Hemoglobin A1c Measurement

Hemoglobin A1c (HbA1c) is used routinely to monitor long-term glycemic control in people with diabetes mellitus, as HbA1c is related directly to risks for diabetic complications. The accuracy of HbA1c methods can be affected adversely by the presence of hemoglobin (Hb) variants or elevated levels of fetal hemoglobin (HbF). The effect of each variant or elevated HbF must be examined with each specific method. The most common Hb variants worldwide are HbS, HbE, HbC, and HbD. All of these Hb variants have single amino acid substitutions in the Hb beta chain. HbF is the major hemoglobin during intrauterine life; by the end of the first year, HbF falls to values close to adult levels of approximately 1%. However, elevated HbF levels can occur in certain pathologic conditions or with hereditary persistence of fetal hemoglobin. In a series of publications over the past several years, the effects of these four most common Hb variants and elevated HbF have been described. There are clinically significant interferences with some methods for each of these variants. A summary is given showing which methods are affected by the presence of the heterozygous variants S, E, C, and D and elevated HbF. Methods are divided by type (immunoassay, ion-exchange high-performance liquid chromatography, boronate affinity, other) with an indication of whether the result is artificially increased or decreased by the presence of a Hb variant. Laboratorians should be aware of the limitations of their method with respect to these interferences.

Host Iron Binding Proteins Acting as Niche Indicators for Neisseria meningitidis

Neisseria meningitidis requires iron, and in the absence of iron alters its gene expression to increase iron acquisition and to make the best use of the iron it has. During different stages of colonization and infection available iron sources differ, particularly the host iron-binding proteins haemoglobin, transferrin, and lactoferrin. This study compared the transcriptional responses of N. meningitidis, when grown in the presence of these iron donors and ferric iron, using microarrays.Specific transcriptional responses to the different iron sources were observed, including genes that are not part of the response to iron restriction. Comparisons between growth on haemoglobin and either transferrin or lactoferrin identified changes in 124 and 114 genes, respectively, and 33 genes differed between growth on transferrin or lactoferrin. Comparison of gene expression from growth on haemoglobin or ferric iron showed that transcription is also affected by the entry of either haem or ferric iron into the cytoplasm. This is consistent with a model in which N. meningitidis uses the relative availability of host iron donor proteins as niche indicators.Growth in the presence of haemoglobin is associated with a response likely to be adaptive to survival within the bloodstream, which is supported by serum killing assays that indicate growth on haemoglobin significantly increases survival, and the response to lactoferrin is associated with increased expression of epithelial cell adhesins and oxidative stress response molecules. The transferrin receptor is the most highly transcribed receptor and has the fewest genes specifically induced in its presence, suggesting this is the favoured iron source for the bacterium. Most strikingly, the responses to haemoglobin, which is associated with unrestricted growth, indicates a low iron transcriptional profile, associated with an aggressive phenotype that may be adaptive to access host iron sources but which may also underlie the lethal features of meningococcal septicaemia, when haemoglobin may become a major source of iron.

Association of Pulmonary Hypertension with Sickle Cell Disease Subtypes

Pulmonary hypertension (PH) is a common complication of sickle cell disease (SD) and a significant cause of morbidity and mortality. PH, measured by Doppler echocardiography and defined as a tricuspid regurgitant jet velocity (TRV) > 2.5 m per second (m/s), is hypothesized to be related to the chronic hemolytic anemia of SD, but causality is unproven. If so, the presence of hemoglobin C, which reduces hemolysis, would be expected to have a reduced likelihood of PH. This study reviewed the prevalence of PH in 3 categories of patients with SD: homozygous S (SS), sickle-beta thalassemia (SB), and SC.Methods: Sickle cell disease patients registered at a state funded community comprehensive care adult sickle cell center were routinely screened for PH by Doppler echocardiography. The presence of PH, the incidence of a related complication, acute chest syndrome (ACS), and baseline hemoglobin (hgb) were reviewed.Results: 16 patients with SC type, 30 with SS and 39 with SB disease underwent screening. The prevalence of PH, ACS and hgb are listed in the table below.Conclusion: SC patients have PH and ACS similar to patients with SS and SB patients. These patients have higher baseline hemoglobin and may have hyperviscosity as a cause of PH and ACS as opposed to hemolytic anemia. Further study of PH and ACS in SC patients is warranted.SCSSSBp valuePH6/16 (38%)12/40 (40%)11/39 (28%)p= NSACS7/16 (44%)10/30 (33%)19/39 (49%)p=NSPH + ACS4/16 (25%)5/30 (17%)4/39 (10%)p=NSACS in PH patients4/6 (67%)5/12 (42%)4/11 (36%)p-=NSHgb10.87.898.57p=0.000

Alloimmunization Does Not Modify the Clinical Profile of Sickle Cell Disease Patients from Salvador-Brazil

Introduction: The hemoglobinopathies are the most common monogenic disorders known. A mutation in the gene for β globin gave origin to hemoglobin S, an abnormal hemoglobin originated in Africa. Sickle cell disease (SCD) is characterized by the presence of hemoglobin S, which results in vasoocclusion episodes and hemolytic anemia throughout patients life. Vascular occlusion leads to acute events and progressive disabling organ damage. Sickle cell anemia is the homozygous state SS, while hemoglobinopathy SC is a doubly heterozygous state, where hemoglobin S occurs in combination with hemoglobin C. Brazil has a prominent African ancestry and SCD is highly prevalent in some regions of the country. In Bahia State, for example, neonatal screening data have shown that, from every 650 children born alive, one has SCD, mostly homozygous SS. Among other therapeutic measures, packed red blood cells (RBC) play a prominent role in SCD management. In situations such as acute chest syndrome (ACS), primary and secondary prevention of stroke, splenic or hepatic sequestration crisis, severe anemia, complicated pregnancy, isquemic organ damages and others, the transfusions may save lives. Although RBC may contribute to reduce morbidity and improve quality of life in SCD patients, there still are risks. Among other risk categories, alloimmunization may result from transfusions and occurs in 5 % to 50 % of SCD patients. It is still not known whether allosensibilization significantly affects the clinical outcomes in SCD.Objecive: The purpose of this study was to compare the clinical profile of multitransfused adult SCD patients who developed alloantibodies (ALO) to patients with the same disease, coming from the same population who did not become alloimmunized (non-ALO).Methods: This is a cross sectional study where medical records of SCD patients, referred to a reference center of Salvador, the capital of Bahia State, Brazil, were reviewed. Only SCD patients 18 years of age or older were included. They had received at least 3 RBC transfusions from 2004 to 2007, or had any alloantibody identified during this period. Patient characteristics, clinical findings, number of transfusions, frequency and specificity of alloantibodies, laboratory data, and the main clinical outcomes were reviewed.Results: a hundred and eight patients were included: 105 SS and 3 SC. The pre-transfusional RBC matching was done to ABH, D,C,c,E,e and Kell antigens. 56 patients developed alloantibodies (53 SS and 3 SC). Anti-E, anti-K, and anti-C were the most prevalent alloantibodies identified (39,3 %, 21,4 % and 16,1 %, respectively). Among the variables addressed in this study, age (higher in non-ALO, .041) and antiglobulin test positivity, more prevalente in ALO (.0001), depicted statistically significant difference. A few patients developed immune hemolysis, controlled successfully with corticosteroids. Alloimmunization was more prevalent among women, although no statistically significant difference was reached between ALO and non-ALO Other variables such as number of transfusions, hematological profile, biochemical data and complications such as stroke, leg ulcers, osteonecrosis, renal disease, abnormal cardiac features, and pulmonary hypertension did not show significant difference between both groups.Conclusion: his study shows that, although alloimmunization is a potential dangerous consequence of RBC transfusions, it did not modify the clinical profile of SCD alloimmunized patients. The concomitance of allosensibilization and autoantibodies in SCD leads to additional difficulties in the RBC matching for transfusion and may exacerbate hemolysis. In order to address autoimmunity in SCD, prospective studies with larger samples are needed.

Increased incidence of iron deficiency anemia secondary to inadequate iron intake in institutionalized, young patients with cerebral palsy

We observed high incidence of anemia in patients with cerebral palsy sheltered in a specialized institution in Thessaloniki, Greece. Therefore, we decided to investigate its cause. We studied 108 patients, and assessed complete blood cell count, peripheral blood smear, serum iron, ferritin, folate, B12 and the presence of hemoglobin or parasites in the stools. In all cases, anemia was hypochromic and microcytic. Approximately 33% of patients suffered from hypochromic anemia, whereas 38% were iron deficient. There was no statistical difference in the incidence of iron deficiency between different age groups. All tests for fecal occult blood or intestinal parasites were negative. Folic acid and B12 levels were within normal range in all cases. We also found that 87 and 95.6% of patients on liquid diet were anemic and iron deficient, respectively, compared to only 18.8 and 22.3% of patients on normal diet. The high incidence of anemia was attributed to iron deficiency which was secondary to inadequate iron intake and decreased iron absorption. Thus, it would not be irrational to consider iron supplementation as the first measure in such patients and postpone endoscopic procedures for a later stage, unless there are clinical or laboratory findings (such as fecal occult blood) suggestive of gastrointestinal blood loss.

Total hemoglobin concentration in amniotic fluid is increased in intraamniotic infection/inflammation

Discolored amniotic fluid (AF) has been associated with intraamniotic infection/inflammation (IAI) in patients with preterm labor (PTL). The presence of hemoglobin and its catabolic products has been implicated as a cause for AF discoloration. The aim of this study was to determine whether there is an association between total hemoglobin concentration in AF and gestational age, spontaneous labor (term and preterm), and the presence or absence of IAI. This cross-sectional study included patients in the following groups: (1) mid trimester (n = 65 patients); (2) term not in labor (n = 22 patients); (3) term in labor (n = 47 patients); (4) spontaneous PTL who delivered at term (n = 92 patients); (5) PTL without IAI who delivered preterm (n = 76 patients); (6) PTL with IAI (n = 81 patients); (7) preterm prelabor rupture of the membranes (PPROM) with IAI (n = 48 patients); and (8) PPROM without IAI (n = 49 patients). Total hemoglobin concentrations in amniotic fluid were determined by an enzyme-linked immunoassay. Nonparametric statistics were used for analysis. Hemoglobin was detected in all AF samples (n = 480). The median AF total hemoglobin concentration at term was significantly higher than in mid trimester (520.6 ng/mL [interquartile range (IQR), 271.2-1549.2] vs 58.5 ng/mL [IQR, 26.1-200.8]; P < .001]). Among patients with PTL, the median AF total hemoglobin concentration was significantly higher in patients with IAI than in patients without IAI (4671.7 ng/mL [IQR, 1294.2-8620.7] vs 2013.6 ng/mL [IQR, 629.2-5420.4]; P = .01) or women who delivered at term (1143.4 ng/mL [IQR, 451.8-4037.9]; P = .001). Similarly, among patients with PPROM, the median AF total hemoglobin concentration was significantly higher in patients with IAI than in patients without IAI (10753.7 ng/mL [IQR, 2053.9-56026.6] vs 2281 ng/mL [IQR, 938.2-9191.7]; P = .02). Women at term in labor had a higher median hemoglobin concentration than did women who were not in labor (1952.6 ng/mL [IQR, 709.6-6289.2] vs 520.6 ng/mL [IQR, 271.1-1549.2]; P = .003). The AF concentration of immunoreactive total hemoglobin increases with advancing gestational age, and is elevated in pregnancies that are complicated with IAI. Spontaneous labor at term is associated with higher AF concentrations of total hemoglobin.