One of our SHO's has just completed an audit into haemolysed
blood specimens. When we started using vacutainers several years ago our
haemolysis rate on samples increased. I wondered whether other departments had
also experienced this? Has anyone else audited this? I'm enclosing an
extract from the audit.
On a second point does anyone routinely take samples from the
venflon put in by the paramedics...... as they always use at least an 18G
and often in a large vein like the cubital fossa it seems a shame not to use
that site... for the patient's sake. I discard the first 5 ml of blood. Anyone
done a study on this?
Ray McGlone
A randomized, prospective study conducted at the emergency dept in
Columbus, Georgia2 where a total of
165 patients were randomized into the IV group (87pts) or the venepuncture
group(78pts) also showed a statistical significant difference (p=0.03) where
more blood was haemolysed when
drawn from the IV catheters ( 13.7%versus 3.8%).
The study also showed a a lower in incidence of haemolysis with larger
catheter diameters (p=0.047); 24 gauge(100%), 22 gauge(25%), 20 gauge(15%), 18
gauge(10%), 16 and 14 gauges(0%).
•
Compared to other A&E departments, RLI has slightly lower or
comparable rates of haemolysis. For instance, when looking at the 598
questionnaire based study at the John Hopkins Hospital 1 ,
Baltimore; 32% of their samples had some degree of haemolysis (compared to 4%
shown here); the study also showed that blood drawn through IV catheters
resulted in significantly more haemolysis than using the needle technique (p<.001). The survey also
demonstrated that the predominant method of drawing blood was by IV catheters
(69%) which was similar to our rate here(72%). The study also showed that IV
catheter haemolysis was higher when a vacutainer was used versus a syringe ( 22%
versus 9%); this was significant at
p=0.02
1.
Grant M. The effect of blood drawing techniques and equipment
on the
haemolysis of ed laboratory samples. J Emerg Nurs 2003;29:116-21.
•
•2. Kennedy C et al. A comparison of haemolysis rates using
intravenous
catheters versus venipuncture tubes for obtaining blood
samples. J Emerg Nurs 1996;22: 566-9.
Ray McGlone