1. Incubation of sample in P-5'-P,
lOO~ol/L
in reagent A.
start with 2-0xoglutarate (l, 2, 5-13)
Advantage: Complete activation in the majority of sera.
Can be automated.
Disadvantage: Prolongs incubation-activation time to 5 minu–
tes.
2. Incubation of sample in complete reagent (8, 14, 15)
Advantage: Serum start is used.
Disadvantage: Complete reactivation is not reached in all
sera.
3. Addition of P-5'-P, 250 pmol/L in TRIS buffer to sample
(7-9, 16, 17)
Advantage: Complete activation.
Serum start is possible.
Disadvantage: Requires an additional, manual analytical step.
The activation time may be as long as 30 minutes,
and the lag-phase increases to 5 minutes or more
for some sera (5, 8, 9)
Increased absorbance at 405 - 410 nm.
The time required for complete activation varies considerably
ru~ong
individual sera. In the IFCC ASAT and ALAT Reference
Methods procedure l and an activation time of lO minutes were
recommended. However, activation by procedure l will be comp–
lete for the majority of sera within 5 minutes. Accordingly,
this activation time was selected for the ECCLS standard Met–
hods 2 - 3 for ASAT and ALAT determinations.
Klinisk kemi
i
Norden 2: supp/, 1990
57
