Dengue Patients’ Hemoglobin Concentrations Compared by POC and CBC

The natural history of dengue has the unique characteristic of plasma leakage that results in hemoconcentration as well as vasculopathy and thrombocytopenia that result in bleeding.

Hematocrit monitoring is a crucial tool to guide management in dengue patients. Microhematocrit adjunct with a complete blood count (CBC) to monitor dengue patients were traditionally performed to decrease the frequency of venipuncture. However, microhematocrit is currently less preferred to the point-of-care hemoglobin monitoring tools to measure red cells in other diseases.

A team of medical scientists at the Ramathibodi Hospital (Bangkok, Thailand) evaluated the relationship between hemoglobin measured by point-of-care hemoglobin (POC-Hb) testing and hematocrit measured by the automated method in adult dengue patients. A total of 44 dengue patients were enrolled. Twenty-nine patients (65.9%) were female, with a median age of 31 years (interquartile range 22–41). Of the enrolled patients, 30 (68.2%), 11 (25.0%), and three (6.8%) were classified as dengue without warning signs, with warning signs, and severe dengue, respectively. Seven patients (15.9%) had hemoconcentration, and five patients (11.3%) had bleeding.

The team measured a CBC by Mindray BC-6800Plus (Mindray, Shenzhen, China) at Ramathibodi Hospital, and Sysmex XN-3000 (Sysmex, Kobe, Japan) at Chakri Naruebodindra Medical Institute. POC-Hb testing was performed on capillary blood and read by the HemoCue Hb 201+ (HemoCue AB, Ängelholm, Sweden). POC-Hb testing was conducted by three physicians who were trained on the use of the device. Hemoconcentration was defined by an increase of ≥20% in hematocrit compared with a convalescent value. A total of 216 pairs of POC-Hb and CBC were evaluated.

The investigators reported that the medians of hemoglobin and hematocrit at dengue presentation were 13.8 g/dL and 41.6%, respectively. The medians of mean corpuscular volume (MCV) and platelets were 87.0 fL and 98,500/mm3, respectively. The team found a significant positive correlation was observed between hemoglobin measured by POC-Hb testing and hematocrit measured by an automated CBC. Bland-Altman analysis between hemoglobin measured by POC-Hb testing and an automated CBC showed a bias of -0.43. Using the cutoff of POC-Hb ≥20% as a criteria for hemoconcentration, the sensitivity and specificity of hemoconcentration detected by POC-Hb device were 71.4% and 100.0%, respectively.

The authors concluded that hemoglobin measurement using POC-Hb testing adjunct with CBC monitoring can be used to monitor plasma leakage as well as hemorrhage in dengue patients. The use of POC-Hb testing is less invasive and requires less blood compared to venipuncture for CBC evaluation. The study was published on August 16, 2021 in the journal PLOS Neglected Tropical Diseases.

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Ramathibodi Hospital
Mindray
Sysmex
HemoCue AB