Comparison of four methods to measure haemoglobin concentrations in whole blood donors (COMPARE): A diagnostic accuracy study

[Comparison of a portable hemoglobinometer (Verio Q Red) with clinical laboratory results in routine clinical practice]

OBJECTIVE

To analyze the concordance between a hemoglobinometer with capillary blood sample and the clinical laboratory with a venous blood sample.

DESIGN

Cross-sectional concordance study.

LOCATION

Care Centre Primary Bufalà-Canyet Primary and Care Centre Primary Dalt la Vila Primary Care Center, Badalona, Barcelona.

PARTICIPANTS

Random selection of participants who attended routine blood tests. Over 18years old. No abandonment or loss was obtained.

MAIN INTERVENTIONS AND MEASUREMENTS

Sex, age, and reason for the blood test were collected from the medical history. Venous blood is drawn, and simultaneously, capillary blood is collected.

RESULTS

120 individuals are included, with an average age of 58.9years. The Bland-Almant graph showed differences within the confidence intervals for hemoglobin and hematocrit. The mean differences between the values of the Verio Q Red hemoglobinometer and those of the clinical laboratory were -0.42mg/dl for hemoglobin and -1.25% for hematocrit. The intraclass correlation coefficient showed excellent correlation for hemoglobin and hematocrit between the Verio Q Red hemoglobinometer and the clinical laboratory. Pearson's correlation for hemoglobin was 0.737 and for hematocrit 0.787.

CONCLUSIONS

The Verio Q hemoglobinometer is a valid tool for the early diagnosis of anemias and can be very useful in primary care consultations.

Prenatal anaemia and risk of postpartum haemorrhage: a cohort analysis of data from the Predict-PPH study

BACKGROUND

Most previous clinical studies investigating the connection between prenatal anaemia and postpartum haemorrhage (PPH) have reported conflicting results.

OBJECTIVES

We examined the association between maternal prenatal anaemia and the risk of PPH in a large cohort of healthy pregnant women in five health institutions in Lagos, Southwest Nigeria.

METHODS

This was a prospective cohort analysis of data from the Predict-PPH study that was conducted between January and June 2023. The study enrolled n = 1222 healthy pregnant women giving birth in five hospitals in Lagos, Nigeria. The study outcome, WHO-defined PPH, is postpartum blood loss of at least 500 milliliters. We used a multivariable logistic regression model with a backward stepwise conditional approach to examine the association between prenatal anaemia of increasing severity and PPH while adjusting for confounding factors.

RESULTS

Of the 1222 women recruited to the Predict-PPH study between January and June 2023, 1189 (97·3%) had complete outcome data. Up to 570 (46.6%) of the enrolled women had prenatal anaemia while 442 (37.2%) of those with complete follow-up data had WHO-defined PPH. After controlling for potential confounding factors, maternal prenatal anaemia was independently associated with PPH (adjusted odds ratio = 1.37, 95% confidence interval: 1.05-1.79). However, on the elimination of interaction effects of coexisting uterine fibroids and mode of delivery on this association, a sensitivity analysis yielded a lack of significant association between prenatal anaemia and PPH (adjusted odds ratio = 1.27, 95% confidence interval: 0.99-1.64). We also recorded no statistically significant difference in the median postpartum blood loss in women across the different categories of anaemia (P = 0.131).

CONCLUSION

Our study revealed that prenatal anaemia was not significantly associated with PPH. These findings challenge the previously held belief of a suspected link between maternal anaemia and PPH. This unique evidence contrary to most previous studies suggests that other factors beyond prenatal anaemia may contribute more significantly to the occurrence of PPH. This highlights the importance of comprehensive assessment and consideration of various maternal health factors in predicting and preventing this life-threatening obstetric complication.

HemoCue Hb-801 Provides More Accurate Hemoglobin Assessment in Blood Donors Than OrSense NBM-200

Hemoglobin levels are commonly assessed to prevent causing or worsening of anemia in prospective blood donors. We compared head-to-head the accuracy of different technologies for measuring hemoglobin suitable for use in mobile donation units. We included 144 persons donating platelets at the Central Institute for Blood Transfusion and Immunology in Innsbruck, Austria. Hemoglobin levels were measured in venous blood using the portable hemoglobinometer HemoCue Hb-801 and noninvasively using OrSense NBM-200, and compared to values obtained with the Sysmex XN-430, an automated hematology analyzer employing the sodium lauryl sulphate method, which is broadly used as reference method in everyday clinical practice. Mean age of participants was 34.2 years (SD 13.0); 34.0% were female. Hemoglobin values measured with HemoCue were more strongly correlated with the Sysmex XN-430 (r = 0.90 [95% CI: 0.87-0.93]) than measured with OrSense (r = 0.49 [0.35-0.60]). On average, HemoCue overestimated hemoglobin by 0.40 g/dL (0.31-0.48) and OrSense by 0.75 g/dL (95% CI: 0.54-0.96). When using OrSense, we found evidence for higher overestimation at higher hemoglobin levels (proportional bias) specifically in females but not in males (Pdifference = .003). Sensitivity and specificity for classifying donors according to the hemoglobin donation thresholds were 99.2% (95% CI: 95.3%-100.0%) and 43.8% (23.1%-66.8%) for HemoCue vs 95.3% (89.9%-98.0%) and 12.5% (2.2%-37.3%) for OrSense. Areas under the receiver operating characteristic curves were higher using HemoCue vs OrSense both in females (0.933 vs 0.547; P = .044) and males (0.948 vs 0.628; P < .001). HemoCue Hb-801 measures hemoglobin more accurately than OrSense NBM-200 in the setting of mobile blood donation units. Our findings are particularly relevant for females, having in mind that anemia is more prevalent in females than in males.

Evaluation of interventions to prevent vasovagal reactions among whole blood donors: rationale and design of a large cluster randomised trial

BACKGROUND

Vasovagal reactions (VVRs) are the most common acute complications of blood donation. Responsible for substantial morbidity, they also reduce the likelihood of repeated donations and are disruptive and costly for blood services. Although blood establishments worldwide have adopted different strategies to prevent VVRs (including water loading and applied muscle tension [AMT]), robust evidence is limited. The Strategies to Improve Donor Experiences (STRIDES) trial aims to reliably assess the impact of four different interventions to prevent VVRs among blood donors.

METHODS

STRIDES is a cluster-randomised cross-over/stepped-wedge factorial trial of four interventions to reduce VVRs involving about 1.4 million whole blood donors enrolled from all 73 blood donation sites (mobile teams and donor centres) of National Health Service Blood and Transplant (NHSBT) in England. Each site ("cluster") has been randomly allocated to receive one or more interventions during a 36-month period, using principles of cross-over, stepped-wedge and factorial trial design to assign the sequence of interventions. Each of the four interventions is compared to NHSBT's current practices: (i) 500-ml isotonic drink before donation (vs current 500-ml plain water); (ii) 3-min rest on donation chair after donation (vs current 2 min); (iii) new modified AMT (vs current practice of AMT); and (iv) psychosocial intervention using preparatory materials (vs current practice of nothing). The primary outcome is the number of in-session VVRs with loss of consciousness (i.e. episodes involving loss of consciousness of any duration, with or without additional complications). Secondary outcomes include all in-session VVRs (i.e. with and without loss of consciousness), all delayed VVRs (i.e. those occurring after leaving the venue) and any in-session non-VVR adverse events or reactions.

DISCUSSION

The STRIDES trial should yield novel information about interventions, singly and in combination, for the prevention of VVRs, with the aim of generating policy-shaping evidence to help inform blood services to improve donor health, donor experience, and service efficiency.

TRIAL REGISTRATION

ISRCTN: 10412338. Registration date: October 24, 2019.

Maternal anaemia and the risk of postpartum haemorrhage: a cohort analysis of data from the WOMAN-2 trial

BACKGROUND

Worldwide, more than half a billion women of reproductive age are anaemic. Each year, about 70 000 women who give birth die from postpartum haemorrhage. Almost all deaths are in low-income or middle-income countries. We examined the association between anaemia and the risk of postpartum haemorrhage.

METHODS

We did a prospective cohort analysis of data from the World Maternal Antifibrinolytic-2 (WOMAN-2) trial. This trial enrols women with moderate or severe anaemia giving birth vaginally in hospitals in Pakistan, Nigeria, Tanzania, and Zambia. Moderate anaemia was defined as a haemoglobin concentration of 70-99 g/L and severe anaemia as less than 70 g/L. Hospitals in each country where anaemia in pregnancy is common were identified from a network established during previous obstetric trials. Women who were younger than 18 years without permission provided by a guardian, had a known tranexamic acid allergy, or developed postpartum haemorrhage before the umbilical cord was cut or clamped were excluded from the study. Prebirth haemoglobin, the exposure, was measured after hospital arrival and just before giving birth. Postpartum haemorrhage, the outcome, was defined in three ways: (1) clinical postpartum haemorrhage (estimated blood loss ≥500 mL or any blood loss sufficient to compromise haemodynamic stability); (2) WHO-defined postpartum haemorrhage (estimated blood loss of at least 500 mL); and (3) calculated postpartum haemorrhage (calculated estimated blood loss of ≥1000 mL). Calculated postpartum haemorrhage was estimated from the peripartum change in haemoglobin concentration and bodyweight. We used multivariable logistic regression to examine the association between haemoglobin and postpartum haemorrhage, adjusting for confounding factors.

FINDINGS

Of the 10 620 women recruited to the WOMAN-2 trial between Aug 24, 2019, and Nov 1, 2022, 10 561 (99·4%) had complete outcome data. 8751 (82·9%) of 10 561 women were recruited from hospitals in Pakistan, 837 (7·9%) from hospitals in Nigeria, 525 (5·0%) from hospitals in Tanzania, and 448 (4·2%) from hospitals in Zambia. The mean age was 27·1 years (SD 5·5) and mean prebirth haemoglobin was 80·7 g/L (11·8). Mean estimated blood loss was 301 mL (SD 183) for the 8791 (83·2%) women with moderate anaemia and 340 mL (288) for the 1770 (16·8%) women with severe anaemia. 742 (7·0%) women had clinical postpartum haemorrhage. The risk of clinical postpartum haemorrhage was 6·2% in women with moderate anaemia and 11·2% in women with severe anaemia. A 10 g/L reduction in prebirth haemoglobin increased the odds of clinical postpartum haemorrhage (adjusted odds ratio [aOR] 1·29 [95% CI 1·21-1·38]), WHO-defined postpartum haemorrhage (aOR 1·25 [1·16-1·36]), and calculated postpartum haemorrhage (aOR 1·23 [1·14-1·32]). 14 women died and 68 either died or had a near miss. Severe anaemia was associated with seven times higher odds of death or near miss (OR 7·25 [95% CI 4·45-11·80]) than was moderate anaemia.

INTERPRETATION

Anaemia is strongly associated with postpartum haemorrhage and the risk of death or near miss. Attention should be given to the prevention and treatment of anaemia in women of reproductive age.

FUNDING

The WOMAN-2 trial is funded by Wellcome and the Bill & Melinda Gates Foundation.

Impact of a post-donation hemoglobin testing strategy on efficiency and safety of whole blood donation in England: A modeling study

BACKGROUND

Deferrals due to low hemoglobin are time-consuming and costly for blood donors and donation services. Furthermore, accepting donations from those with low hemoglobin could represent a significant safety issue. One approach to reduce them is to use hemoglobin concentration alongside donor characteristics to inform personalized inter-donation intervals.

STUDY DESIGN AND METHODS

We used data from 17,308 donors to inform a discrete event simulation model comparing personalized inter-donation intervals using "post-donation" testing (i.e., estimating current hemoglobin from that measured by a hematology analyzer at last donation) versus the current approach in England (i.e., pre-donation testing with fixed intervals of 12-weeks for men and 16-weeks for women). We reported the impact on total donations, low hemoglobin deferrals, inappropriate bleeds, and blood service costs. Personalized inter-donation intervals were defined using mixed-effects modeling to estimate hemoglobin trajectories and probability of crossing hemoglobin donation thresholds.

RESULTS

The model had generally good internal validation, with predicted events similar to those observed. Over 1 year, a personalized strategy requiring ≥90% probability of being over the hemoglobin threshold, minimized adverse events (low hemoglobin deferrals and inappropriate bleeds) in both sexes and costs in women. Donations per adverse event improved from 3.4 (95% uncertainty interval 2.8, 3.7) under the current strategy to 14.8 (11.6, 19.2) in women, and from 7.1 (6.1, 8.5) to 26.9 (20.8, 42.6) in men. In comparison, a strategy incorporating early returns for those with high certainty of being over the threshold maximized total donations in both men and women, but was less favorable in terms of adverse events, with 8.4 donations per adverse event in women (7.0, 10,1) and 14.8 (12.1, 21.0) in men.

DISCUSSION

Personalized inter-donation intervals using post-donation testing combined with modeling of hemoglobin trajectories can help reduce deferrals, inappropriate bleeds, and costs.

Early detection of anaemia in primary care with haemoglobinometry: ANHEMOG clinical trial protocol

Abstract

Background

Detecting, treating and monitoring anaemia has a functional, social and economic impact on patients’ quality of life and the health system, since inadequate monitoring can lead to more accident & emergency visits and hospitalizations. The aim of this study is to evaluate the impact in the patient clinical outcomes of using haemoglobinometry to early detect anaemia in patients with chronic anaemia in primary care.

Methods

Randomized controlled trial Capillary haemoglobin will be measured using a haemoglobinometer on a monthly basis in the intervention group. In the control group, the protocol currently in force at the primary care centre will be followed and venous haemoglobin will be measured. Any cases of anaemia detected in either group will be referred to the transfusion circuit of the reference hospital.

Discusion

The results will shed light on the impact of the intervention on the volume of hospitalizations and accident & emergency (A&E) visits due to anaemia, as well as patients’ quality of life. Chronic and repeated bouts of anaemia are detected late, thus leading to decompensation in chronic diseases and, in turn, more A&E visits and hospitalizations. The intervention should improve these outcomes since treatment could be performed without delay. Improving response times would decrease decompensation in chronic diseases, as well as A&E visits and hospitalizations, and improve quality of life. The primary care nurse case manager will perform the intervention, which should improve existing fragmentation between different care levels.

Trial registration

NCT04757909. Registered 17 February 2021. Retrospectively registered.

Donation-induced iron depletion is significantly associated with low hemoglobin at subsequent donations

BACKGROUND

Blood donation is associated with a loss of hemoglobin (Hb)-bound iron. Hb levels recover relatively fast by using stored iron. However, it takes more time to replenish iron stores, potentially resulting in iron deficiency.

STUDY DESIGN

Hb and ferritin levels were measured in 5056 new, first-time, and repeat whole blood donors. We investigated whether increasing numbers of donations are associated with lower ferritin levels. Furthermore, we tested whether low ferritin levels are associated with low-Hb deferral at the subsequent donation attempt by performing logistic regression adjusted for age and stratified by sex.

RESULTS

Whereas mean Hb levels are relatively stable, ferritin levels significantly decrease with increasing numbers of donations and were approximately 50% lower for donors with >50 donations compared with those with 2-10 donations. Despite the poor correlation of ferritin and Hb levels, cross-sectional, iron-deficient donors (ferritin <15 ng/ml) had 21.8 (8.5-55.6) higher odds in men, 10.1 (6.1-16.5) in premenopausal women, and 11.7 (5.2-26.4) in postmenopausal women for Hb deferral at a subsequent visit.

DISCUSSION

To conclude, repeated donations may induce iron deficiency, which corresponds with an over tenfold increased risk of having insufficiently restored Hb levels at a subsequent donation attempt. Longer donation intervals and/or higher dietary or supplemental iron intake are warranted to prevent accumulated iron depletion and subsequent low-Hb deferral in whole blood donors.

Comparison of four methods to measure haemoglobin concentrations in whole blood donors (COMPARE): A diagnostic accuracy study

OBJECTIVE

To compare four haemoglobin measurement methods in whole blood donors.

BACKGROUND

To safeguard donors, blood services measure haemoglobin concentration in advance of each donation. NHS Blood and Transplant's (NHSBT) customary method have been capillary gravimetry (copper sulphate), followed by venous spectrophotometry (HemoCue) for donors failing gravimetry. However, NHSBT's customary method results in 10% of donors being inappropriately bled (ie, with haemoglobin values below the regulatory threshold).

METHODS

We compared the following four methods in 21 840 blood donors (aged ≥18 years) recruited from 10 NHSBT centres in England, with the Sysmex XN-2000 haematology analyser, the reference standard: (1) NHSBT's customary method; (2) "post donation" approach, that is, estimating current haemoglobin concentration from that measured by a haematology analyser at a donor's most recent prior donation; (3) "portable haemoglobinometry" (using capillary HemoCue); (4) non-invasive spectrometry (using MBR Haemospect or Orsense NMB200). We assessed sensitivity; specificity; proportion who would have been inappropriately bled, or rejected from donation ("deferred") incorrectly; and test preference.

RESULTS

Compared with the reference standard, the methods ranged in test sensitivity from 17.0% (MBR Haemospect) to 79.0% (portable haemoglobinometry) in men, and from 19.0% (MBR Haemospect) to 82.8% (portable haemoglobinometry) in women. For specificity, the methods ranged from 87.2% (MBR Haemospect) to 99.9% (NHSBT's customary method) in men, and from 74.1% (Orsense NMB200) to 99.8% (NHSBT's customary method) in women. The proportion of donors who would have been inappropriately bled ranged from 2.2% in men for portable haemoglobinometry to 18.9% in women for MBR Haemospect. The proportion of donors who would have been deferred incorrectly with haemoglobin concentration above the minimum threshold ranged from 0.1% in men for NHSBT's customary method to 20.3% in women for OrSense. Most donors preferred non-invasive spectrometry.

CONCLUSION

In the largest study reporting head-to-head comparisons of four methods to measure haemoglobin prior to blood donation, our results support replacement of NHSBT's customary method with portable haemoglobinometry.