The Clinical Relevance of Nucleated Red Blood Cell Counts

• The Clinical Relevance of Nucleated Red Blood Cell Counts

AUTHOR(S)

M. SCHAEFER and R. M. ROWAN

Sysmex Europe GmbH

SUMMARY

The pattern across laboratory medicine during the past thirty years has been one of increasing demand for tests combined with a need for cost containment. The latter has now become an over-riding consideration. It is no longer more work for the same number of technologists but more work for fewer individuals since staff represents the major expenditure in most clinical laboratories. Fortunately, incremental advances in instrumentation, particularly in the area of blood cell counting, have accompanied these increasing economic pressures and this has resulted in a reduction in the need for manual and semi-automated processing. The most recent addition is the ability, with some instruments, to enumerate nucleated red blood cells ( NRBC ). This inevitably poses the question: is there clinical value in counting NRBC? At the moment examination of blood cell morphology by microscopy remains one of the major labour intensive non-automated procedures conducted in the haematology laboratory. It is a perpetual challenge to reduce the number of peripheral blood films examined but at the same time not miss valuable diagnostic pointers. Some laboratories cling to the hallowed tradition that examination of the peripheral blood is incomplete without a blood film report. This luxury becomes impossible in the high throughput laboratory where a film review rate greater than 10 - 15 % becomes impossible to manage. This low review rate does not appear to result in significant loss of screening or diagnostic capability. The blood film is examined for a number of reasons: to explain an unexpected blood count finding, to examine red cell morphology, to verify an unexplained automated differential leukocyte count or to undertake an extended differential count. For the last, the most frequently occurring findings are the presence of immature granulocytes and NRBC. It is therefore important to recognise the pres-ence of NRBC with confidence but is it necessary to produce an accurate NRBC count? The simple answer is affirmative if for no other reason than the ability to produce a correct total leukocyte count and a correct differential leukocyte count.

KEY WORDS

Nucleated Red Blood Cell ( NRBC ), Automated Counting