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Improving clinical efficiency through LSRB automation

Giorgio Da Rin
1 July, 2006  

Giorgio Da Rin MD
Director
Laboratory Medicine
San Bassiano Hospital
Bassano del Grappa
Italy

The measurement of the length of sedimentation reaction in  blood (LSRB) – commonly but improperly called erythrocyte  sedimentation rate (ESR) – is a simple, routine laboratory  technique. LSRB, the most widely used laboratory measure of  disease activity in clinical medicine, is still considered  useful for monitoring inflammatory diseases, particularly  rheumatoid arthritis.

Recent reviews indicate that this test is widely used both  for the diagnosis and the follow-up of patients with these  conditions.(1-4) In fact, the value of LSRB in many  rheumatologic diseases is well established. In particular,  it is one of the criteria used for the diagnosis of  polymyalgia rheumatica and giant cell arteritis, and for the  monitoring of these and other rheumatologic diseases. A  normal LSRB reduces the negative likelihood ratio of  temporal arteritis to 0.2, and only 4% of patients with the  disease present LSRB of 30mm or less. In polyarthralgia, the  value of LSRB correlates well with the number of pain  affected joints and it is a valuable marker of disease  activity. In early rheumatoid arthritis, LSRB predicts the  progression of joint damage.

While LSRB maintains its important role in the diagnosis and  follow-up of rheumatoid arthritis, temporal arteritis and  polymyalgia, it was recently reported to be of clinical  significance in sickle cell disease, osteomyelitis and,  surprisingly, in conditions such as stroke and coronary  artery disease.(5-12) In acute coronary syndrome, LSRB  testing has been described as being of prognostic value and  an independent predictor of mortality – possibly confirming  that the inflammatory cascade is causally involved in plaque  rupture and thrombosis. In oncology, a high LSRB has been  found to correlate with poor prognosis for various types of  cancer, including Hodgkin’s disease. European studies of  patients with Hodgkin’s disease suggest that an elevated  LSRB may still be an excellent predictor of early  relapse.(13)

San Bassiano Hospital
The laboratory at San Bassiano Hospital, Bassano del Grappa,  Italy, provides a wide range of routine and specialised  testing and clinical consultation to support diagnosis. It  also monitors treatments of hospital inpatients and a large  number of outpatients. The laboratory performs approximately  2.4 million tests/year, 50,000 of which are LSRB, and  employs 35 fulltime staff. Modern laboratories committed to  providing state-of-the-art, cost- effective testing,  regularly translate developing technology into routine  practice – by adopting new tests and improving upon existing  ones. With this in mind we reorganised the haematology  section of the laboratory in 2005. In relation to LSRB we  are aiming to:

  • Guarantee safety of operators by using automated and  closed systems.
  • Automate the measurement process and optimise the workflow  and the utilisation of staff.
  • Create a unique workstation for measuring LSRB and  performing other haematological tests (eg, erythrocyte,  leukocyte and reticulocyte concentrations) in a single  specimen.
  • Make the results of the test more widely and quickly  available to physicians.
  • Use a reference specimen (the undiluted specimen collected  in K2EDTA) that is more reliable than the traditional sodium  citrate as suggested by the International Council for  Standardization in Haematology and the Clinical and  Laboratory Standards Institute.

A new automatic system
Until recently, LSRB testing was performed using VES-matic  (Diesse), a closed analyser programmed for the simultaneous  determination of LSRB in 60 blood samples, which used  rectangular plastic vacuum tubes containing sodium citrate  as anticoagulant. In line with the reorganisation, we  adopted VES-cube (Diesse), a new, closed automatic system  for determining LSRB in K2EDTA tubes. The sample loader  houses 20 racks, the same ones used by automated haematology  analyser in random access mode. The system automatically  reveals the erythrocyte sedimentation level by using two  optoelectronic elements (LED + analogical photosensor). Data  are then elaborated, printed and sent to the host computer.  The system operates at a rate of 120 samples for the first  hour and then at 190 samples/hour. The first result is  obtained after 20 minutes and the following ones every 18  seconds. The samples in which LSRB is performed are  automatically placed in a collecting rack. Their positions  are identifiable by the instruments with alphanumeric  coordinates, facilitating future research. The system  possesses  software that manages quality control, which is  based on analysis of a stable control material.

Positive results
The advantages of using the VES-cube analyser in a clinical  laboratory are reported as being: safety for operators, full  automation, reduced turnaround time and limited analytic  imprecision. However, in our opinion one of the major  benefits is the use of undiluted K2EDTA-anticoagulated  samples.

It is well known that LSRB is affected by red blood cell  (RBC) aggregation or “rouleau” formation. In the blood of  normal patients, RBCs suspended in the blood do not  aggregate because they repel each other on account of their  negative electric charge. In some pathological conditions we  encounter a rise of plasmatic proteins as fibrinogens,  gamma-globulins and alpha-globulins. These proteins, which  have a positive charge, neutralise the RBC’s negative  charges and promote the formation of erythrocytes  agglomerate, which have the appearance of a coin pile or  “rouleau”, that cause an increase of the erythrocytes  sedimentation. However, some RBC morphological alterations  (eg, anisocytosis and spherocytosis) may prevent rouleau  formation because their morphology inhibits erythrocyte  aggregation.

The collection of specimens with K2EDTA enhances blood cell  stability, preserving morphologic features and obviating  unphysiologic effects on the cells, and therefore favours  rouleau formation. LSRB analysis from the same sample as the  haematology analyser leads to further improvement: a smaller  sample volume is required (particularly useful in newborns,  children and oncology patients), sample collection and  handling costs are reduced, and the use of the same racks as  haematology analysers, available in random access,  contributes in optimising the workflow in clinical  laboratories.

In the past, two separate samples had to be used: one for  the haematology analyser and one for the LSRB analyser. Now,  with a single sample, we have a reduction in: the handover  of samples in the laboratory; biological waste (reduction  approximately 350kg/year); the amount of blood that needs to  be taken (estimated reduction is 50 litres/year); and  phlebotomy time (approximately 10 seconds/patient). Time  saved by operators on the one hand is an advantage in poorly  staffed teams, but on the other it can be used to improve  relational aspects with patients. Furthermore, the use of  undiluted and anti-coagulated blood with K2EDTA reduces the  risk of preanalytic mistakes caused by small blood clots or  partially coagulated specimens, or by an altered  blood/sodium citrate ratio. The use of standard test tubes  instead of rectangular ones permits more precision when  taking samples of blood.

The traceability of the K2EDTA tube selected by LSRB,  together with the possibility of using a stable control to  monitor precision and bias – although the LSRB procedure  cannot be calibrated and it is inherently stable – is very  important in relation to quality assurance, certification  and accreditation given that clinical laboratories must  document the quality of LSRB measurements.

Conclusion
This innovative analyser has many advantages (eg, reducing  analytical time and improving productivity, analytical  precision and accuracy). Analytical improvements, however,  are not enough. While the main task of laboratory scientists  used to be control and improving the analytical part of the  total testing process with reliable results, today they also  need to evaluate the appropriateness of test requests. The  usefulness of the tests in clinical practice, clinical  efficacy of laboratory results and their impact on clinical  outcome must also be evaluated, therefore maximising the  impact of laboratory information on patient management.

References

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