Figure 1

Recommended sequence of N specimens in a run

For total cholesterol		For HDL-cholesterol
1)	Reagent blank	1)	Reagent blank
2)	Reagent blank	2)	Reagent blank
3)	Standard 1 (low, 2.60 mmol/l e.g.)	3)	Standard 1 (very low, 0.65 mmol/l e.g.)
4)	Standard 1 (low, 2.60 mmol/l e.g.)	4)	Standard 1 (very low, 0.65 mmol/l e.g.)
5)	Standard 2 (medium, 5.20 mmol/l e.g.)	5)	Standard 2 (low, 1.30 mmol/l e.g.)
6)	Standard 2 (medium, 5.20 mmol/l e.g.)	6)	Standard 2 (low, 1.30 mmol/l e.g.)
7)	Standard 3 (elevated, 7.80 mmol/l e.g.)	7)	Standard 3 (low, 2.60 mmol/l e.g.)
8)	Standard 3 (elevated, 7.80 mmol/l e.g.)	8)	Standard 3 (low, 2.60 mmol/l e.g.)
9)	TC+HDL-C pool, non-precipitated	9)	TC+HDL-C pool supernatant
10)	TC+HDL-C pool, non-precipitated	10)	TC+HDL-C pool supernatant
11)	LTC pool, non-precipated	11)	LTC-pool, non-precipated
12)	LTC pool, non-precipated	12)	LTC-pool, non-precipated

13)	IQC pool for monitoring drift
14)	Patient sample
15)	Patient sample
16)	Patient sample
etc
...
...
23)	IQC pool for monitoring drift
24)	Patient sample
...	Patient sample
...	Patient sample
...	Patient sample

N-1)	TC+HDL-C pool - at end of run	N-1)	TC+HDL-C pool - at end of run
N)	TC+HDL-C pool - at end of run	N)	TC+HDL-C pool - at end of run

Note:

HDL-cholesterol should preferably be analysed in separate runs (or parts of runs) to avoid between sample transfer contamination(s) depending on the instrumentation ("carry over")
Whenever a significant carry-over (e.g. with older photometers) can be expected, it will be necessary to wash out the photometer cuvette first (notably between "high" standard(s) and first IQC samples) with a part of the next sample-reagent mixture and take the reading on the rest of it.