Adult patient:
Clotted blood tube
(Serum gel separator clot activator tube)
Minimum blood volume: 5 mL
Paediatric patient:
Paediatric clotted blood tube
Number of vials: 1
Minimum blood volume: 0.8 mL
Authorisation code required
Yes
24 Hr available service
Yes
Method
Spectrophotometry
Reference interval
| Children, men and women (> 40 years): | 5,320 – 12,900 U/L |
| Women (16 – 39 years, not pregnant nor on contraceptives): | 4,260 – 11,250 U/L |
| Women (18 – 41 years, pregnant or on contraceptives): | 3,650 – 9,129 U/L |
(Source: manufacturers kit insert)
Clinical indication
Prolonged apnoea following suxamethonium (Scoline) or mivacurium
Indicator of possible organophosphate poisoning
Result interpretation
Susceptibility to Scoline apnoea is inherited as an autosomal recessive disorder; cholinesterase activity is usually, but not always, low. Dibucaine and fluoride numbers improve the sensitivity and specificity of the test. Family studies should be done so that other affected individuals can be cautioned against exposure to suxamethonium or mivacurium.
Organophosphate poisoning only temporarily reduces the activity of this enzyme, making it useful for the detection of repeated acute poisoning.
Low levels are also found in pregnancy and in patients with hepatocellular disease.
Measurement of uncertainty
Frequency of measurement
Daily