Accuracy and Reliability of Pallor for Detecting Anaemia: A Hospital-Based Diagnostic Accuracy Study

Abstract

BackgroundAnaemia is a common disorder. Most health providers in resource poor settings rely on physical signs to diagnose anaemia. We aimed to determine the diagnostic accuracy of pallor for anaemia by using haemoglobin as the reference standard.Methodology/Principal FindingsIn May 2007, we enrolled consecutive patients over 12 years of age, able to consent and willing to participate and who had a haemoglobin measurement taken within a day of assessment of clinical pallor from outpatient and medicine inpatient department of a teaching hospital. We did a blind and independent comparison of physical signs (examination of conjunctivae, tongue, palms and nailbed for pallor) and the reference standard (haemoglobin estimation by an electronic cell counter). Diagnostic accuracy was measured by calculating likelihood ratio values and 95% confidence intervals (CI) at different haemoglobin thresholds and area under the receiver operating characteristic curve. Two observers examined a subset of patients (n = 128) to determine the inter-observer agreement, calculated by kappa statistics. We studied 390 patients (mean age 40.1 [SD 17.08] years); of whom 48% were women. The haemoglobin was <7 g/dL in 8% (95% confidence interval, 5, 10) patients; <9 g/dL in 21% (17, 26) patients and <12 g/dL in 64% (60, 70) patients. Among patients with haemoglobin <7 g/dL, presence of severe tongue pallor yielded a LR of 9.87 (2.81, 34.6) and its absence yielded a LR of 0. The tongue pallor outperformed other pallor sites and was also the best discriminator of anaemia at haemoglobin thresholds of 7 g/dL and 9 g/dL (area under the receiver operating characteristic curves (ROC area = 0.84 [0.77, 0.90] and 0.71[0.64, 0.76]) respectively. The agreement between the two observers for detection of anaemia was poor (kappa values = 0.07 for conjunctival pallor and 0.20 for tongue pallor).Conclusions/SignificanceClinical assessment of pallor can rule out and modestly rule in severe anaemia.

Usefulness of examination of palmar creases for assessing severity of anemia in Indian perspective: A study from a tertiary care center

“…[2] A separate study suggested tongue pallor for ruling in severe anemia instead of palmar crease pallor. [18] The results were quite similar to our study as our study suggested that absence of palmar crease pallor does not rule out severe anemia and severe tongue pallor has highest sensitivity for severe anemia (88%). Another study revealed that different pallor sites including conjunctiva, nail-bed and palm were equally useful for detecting severe anemia, however palmar creases were not mentioned specifi cally.…”

Toward laboratory blood test-comparable photometric assessments for anemia in veterinary hematology

“…16,19,48 Although conjunctival pallor is valuable information as a clinical sign for severe anemia, it cannot provide reliable diagnosis in clinical settings. Further, quantification of Hgb from conjunctival pallor using digital photography has received attention.…”

“…12,13 Indeed, optical assessment of the inner eyelid has received attention in anemic patients for assessing Hgb content from human individuals, which could be highly correlated with a lab-based blood Hgb test. [14][15][16][17][18][19] For accurate and precise Hgb measurements, typical spectroscopic technologies heavily rely on the use of spectrometers, spectrographs, and liquid tunable crystal filters. 20,21 However, these critical optical components for highly accurate and sensitive Hgb measurements significantly limit the development of compact, portable, and cost-effective devices.…”

A Study of Distribution and Prevalence of Anaemia in School Going Children of Ghaziabad

“…Kalantri et al have documented that physical estimation of pallor for detection of anaemia strongly correlates with laboratory estimation of haemoglobin. [20] JMSCR Vol||06||Issue||03||Page 1170-1174||March 2018…”