Table 1_Diagnostic accuracy of a non-invasive spot-check hemoglobin meter, Masimo Rad-67® pulse CO-Oximeter®, in detection of anemia in antenatal care settings in Kenya.docx

BackgroundPoint of care hemoglobin meters play key roles in increasing access to anemia screening in antenatal care especially in settings with limited access to laboratories. We aimed to determine the diagnostic accuracy of a non-invasive spot-check hemoglobin (SpHb) meter, Masimo Rad-67® Pulse CO-Oximeter®, in the diagnosis of anemia in pregnant women attending antenatal care clinics in Kilifi, Kenya.
MethodsThis was a diagnostic accuracy study that retrospectively evaluated SpHb against a validated reference standard of laboratory assessed hemoglobin (Lab Hb) by a SYSMEX XN-330 automated hematology analyzer. The study was nested within a prospective pregnancy cohort study that recruited unselected pregnant women from antenatal care clinics in two public hospitals in Kilifi County, coastal Kenya. Records with both SpHb and Lab Hb were selected from pregnancy visits between May 2021 and December 2022. Linear regression and Bland-Altman analysis were performed to compare the two tests and diagnostic accuracy parameters obtained for the diagnosis of anemia.
ResultsA total of 2,975 records (from 2,203 unique participants), with paired SpHb and Lab Hb were analyzed. Linear regression showed a significant but weak positive correlation, a proportional bias of 0.44 (95% CI 0.41–0.47) and a constant of 7.59 (95% CI 7.30–7.87, p < 0.001). The median bias was 1.70 g/dl, with limits of agreement of −0.80 to 4.20. SpHb tended to be higher than Lab Hb on the low hemoglobin range but lower than Lab Hb on the high hemoglobin range. The sensitivity of SpHb in detecting anemia was 18.66%. Prevalence, specificity, positive predictive value, and negative predictive values were 46.37%, 96.77%, 83.33%, and 57.92% respectively.
ConclusionOverall, SpHb by Masimo Rad-67® Pulse CO-Oximeter® did not accurately identify pregnant women with anemia and many cases would be missed. We would not recommend its use in antenatal care settings.

研究背景：床旁血红蛋白检测仪（point of care hemoglobin meters）在提升产前贫血筛查可及性方面发挥关键作用，尤其适用于实验室资源匮乏的场景。本研究旨在评估无创即时检测血红蛋白（spot-check hemoglobin, SpHb）检测仪——迈心诺Rad-67®脉搏碳氧血氧仪（Masimo Rad-67® Pulse CO-Oximeter®）——在肯尼亚基利菲地区产前门诊孕妇贫血诊断中的诊断准确性。
研究方法：本研究为诊断准确性研究，以希森美康（SYSMEX）XN-330全自动血液分析仪检测的实验室血红蛋白（Lab Hb）作为经过验证的参考标准，对SpHb进行回顾性评估。本研究嵌套于一项前瞻性妊娠队列研究，该队列从肯尼亚沿海基利菲县两家公立医院的产前门诊招募未经过筛选的孕妇。研究纳入2021年5月至2022年12月期间，同时具备SpHb与Lab Hb检测记录的妊娠就诊数据。采用线性回归与Bland-Altman分析对两种检测方法进行比较，并计算贫血诊断相关的诊断准确性参数。
研究结果：本研究共分析2975条检测记录（来自2203名独特受试者），所有记录均包含配对的SpHb与Lab Hb数据。线性回归分析显示二者存在显著但微弱的正相关，比例偏倚为0.44（95%置信区间：0.41~0.47），截距项为7.59（95%置信区间：7.30~7.87，p<0.001）。中位偏倚为1.70g/dl，一致性界限为-0.80~4.20g/dl。在血红蛋白浓度较低的区间内，SpHb检测值通常高于Lab Hb；而在血红蛋白浓度较高的区间内，SpHb检测值则低于Lab Hb。SpHb检测贫血的灵敏度为18.66%。该研究人群的贫血患病率、特异度、阳性预测值与阴性预测值分别为46.37%、96.77%、83.33%与57.92%。
研究结论：总体而言，迈心诺Rad-67®脉搏碳氧血氧仪（Masimo Rad-67® Pulse CO-Oximeter®）检测的SpHb无法准确识别贫血孕妇，会漏诊大量病例。因此不推荐将其应用于产前保健场景。