A quality assurance scheme for the Kleihauer test: the Scottish experience 1988–1996

Raafat, Aml; Fraser, N.; Main, Rhonda Ingram; Urbaniak, S. J.

doi:10.1046/j.1365-3148.1997.d01-30.x

Cited by 10 publications

(15 citation statements)

References 4 publications

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“…These data are very close to those obtained by other investigators performing flow cytometry with a single marker 17,38,40,41 . They confirm that flow cytometry is more precise than the KBT known to have a poor reproducibility 4,42 despite several attempts to standardize the method 43 and the introduction of external quality assurance scheme for Kleihauer testing 44 . Two major reasons may explain these findings.…”

Section: Discussionsupporting

confidence: 87%

Identification and quantification of fetal red blood cells in maternal blood by a dual‐color flow cytometric method: evaluation of the Fetal Cell Count kit

Porra¹,

Bernaud²,

Guéret³

et al. 2007

Transfusion

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Section: Discussionsupporting

confidence: 87%

Identification and quantification of fetal red blood cells in maternal blood by a dual‐color flow cytometric method: evaluation of the Fetal Cell Count kit

Porra¹,

Bernaud²,

Guéret³

et al. 2007

Transfusion

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“…This analysis shows the inter-observer CV% of each triplicate set vs. the expected FMH volume (ml). 1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 However, while KBT reagents are inexpensive and the test is simple to perform, confidence in the method has been seriously undermined by its well-recognized technical limitations and poor performance characteristics (Dupre et al, 1993;Mollison et al, 1993;Duckett & Constantine, 1997;Raafat et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

“…Stained films were microscopically examined (×10 eyepiece, ×40 objective and a graticule marked with a 10‐mm 2 grid of 100 squares) to determine the relative frequency of foetal red cells using the method described by Raafat et al. (1997).…”

Section: Kbt Measurement Of Fmhmentioning

confidence: 99%

“…The dye stains only foetal red cells, which are still haemoglobinized while the adult red cells appear as 'ghosts'. Stained films were microscopically examined (·10 eyepiece, ·40 objective and a graticule marked with a 10-mm 2 grid of 100 squares) to determine the relative frequency of foetal red cells using the method described by Raafat et al (1997). This was achieved by determining the average number of RBC in a high power field (hpf) by enumerating individual hpf, then counting the total number of foetal red cells in 100 individual hpf.…”

Section: Kbt Measurement Of Fmhmentioning

confidence: 99%

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Immunocytometric quantitation of foeto-maternal haemorrhage with the Abbott Cell-Dyn CD4000 haematology analyser

et al. 2005

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This study evaluated the extended use of a haematology analyser (Abbott Cell-Dyn CD4000) for the immunofluorescent enumeration of foeto-maternal haemorrhage (FMH) with fluorescein isothiocyanate-labelled monoclonal anti-RhD. Method performance was assessed with artificial FMH standards, and a series of 44 clinical samples. Within run precision was <15% (coefficient of variation, CV) for FMH volumes of 3 ml and above, 18.8% at an FMH volume of 2 ml and 31.7% at an FMH volume of 1 ml. Linearity analysis showed excellent agreement (observed FMH% = 0.98x expected FMH% + 0.02), and a close relationship (R(2) = 0.99) between observed and expected FMH percentages. The lower limit of quantification of the CD4000 (SRP-Ret) method with a maximum CV of 15% was 1.6 ml, and the limit of detection was <1 ml. Parallel Kleihauer-Betke test (KBT) assessments of FMH standards showed an overall trend for higher KBT values (observed = 1.25x expected - 0.38). At an FMH level of 4 ml, KBT observer estimates ranged from 0.57 to 11.94 ml with a mean inter-observer CV of 63%. For 44 clinical samples, there was decision point agreement between KBT and SRP-Ret results for 42 samples with an FMH of <2 ml. Analysis in the low FMH range (<1 ml) showed that small volume foetal leaks could be detected with the SRP-Ret method in most of 23 samples with negative KBT results. CD4000 SRP-Ret method performance for FMH determination was similar to that reported for flow cytometry.

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“…Key problems include poor standardization of counting methodology and significant difficulties in identifying and enumerating maternal ghost red cells. Better standardization of microscope fields and the use of a graticule eyepiece to assist counting have improved performance (Raafat et al ., 1997), but a considerable degree of subjectivity in cell counting remains. The current UK guidelines (BCSH, 1999) recommend the use of flow cytometry to provide accurate assessment of FMH in excess of 4 mL, but many laboratories do not have immediate access to such technology, and initial clinical management is based on the results of a manual technique.…”

mentioning

confidence: 99%

A modified Kleihauer technique for the quantification of foetomaternal haemorrhage

Howarth

Robinson

Williams

et al. 2002

Transfusion Medicine

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The Kleihauer technique, based on acid elution of maternal red cells, is the mostly widely used technique in the UK to screen for, and estimate the volume of, foetomaternal haemorrhage (FMH) and for determining the need for additional doses of anti-D immunoglobulin to prevent maternal alloimmunization. However, technicians often report difficulties in identifying and accurately counting maternal red cells in the blood film, leading to imprecision in the calculated FMH. In this report, we describe a simple modification of the standard Kleihauer technique, based on performing acid elution of only half of the film. Compared to the standard method, the modified technique showed improved accuracy and reduced interobserver variability across a range of simulated FMH volumes. There was a high degree of correlation between the new technique and FMH estimated by flow cytometry (r2 = 0.916, P < 0.001). Technicians found the new technique easy to incorporate into routine practice in a busy teaching hospital laboratory and were impressed by the relative ease of counting maternal ghost cells. The modified technique has been used routinely in our laboratory for 3 years, during which time our performance in the UK National External Quality Assurance Scheme for FMH has been uniformly satisfactory.

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A quality assurance scheme for the Kleihauer test: the Scottish experience 1988–1996

Cited by 10 publications

References 4 publications

Identification and quantification of fetal red blood cells in maternal blood by a dual‐color flow cytometric method: evaluation of the Fetal Cell Count kit

Identification and quantification of fetal red blood cells in maternal blood by a dual‐color flow cytometric method: evaluation of the Fetal Cell Count kit

Immunocytometric quantitation of foeto-maternal haemorrhage with the Abbott Cell-Dyn CD4000 haematology analyser

A modified Kleihauer technique for the quantification of foetomaternal haemorrhage

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