Kalkulace COB

How does AAPS calculate the COB value?

When carbs are entered as part of a meal or correction, AAPS adds them to the current carbs on board (COB). AAPS then absorbs (removes) carbs based on observed deviations to BG values. The rate of absorption depends on the carb sensitivity factor. This is not a profile value but is calculated as ISF/IC and is how many mg/dl 1g of carbs will raise your BG.

The formula is: absorbed_carbs = deviation * ic / isf It means:

  • increasing ic will increase carbs absorbed every 5 minutes thus shorten total time of absorption

  • increasing isf will decrease carbs absorbed every 5 minutes thus prolong total time of absorption

  • changing profile % increase/decrease both values thus has no impact on carbs absorption time

For example, if your profile ISF is 100 and your IC is 5, your CSF would be 20. For every 20 mg/dl your BG goes up, 1g of carbs are absorbed by AAPS. Positive IOB also effects this calculation. So, if AAPS expected your BG to go down by 20 mg/dl because of IOB and it instead stayed flat, it would also absorb 1g of carbs.

Carbs will also be absorbed via the methods described below based on what sensitivity algorithm is used.


Nestrávené sacharidy jsou odříznuty po určené době


AAPS, Vážený průměr

absorption is calculated to have COB == 0 after specified time

AAPS, Vážený průměr

Jestliže je použitá minimální absorpce sacharidů (min_5m_carbimpact) namísto hodnoty vypočtené z odchylek, tak se v COB grafu objeví oranžová tečka.

Zjišťování nesprávných hodnot COB

AAPS warns you if you are about to bolus with COB from a previous meal and the algorithm thinks that current COB calculation could be wrong. V takovém případě Vám bude po použití bolusové kalkulačky zobrazen dodatečný pokyn na obrazovce s potvrzením.

How does AAPS detect wrong COB values?

Obvykle AAPS detekuje absorpci sacharidů prostřednictvím odchylek glykémií. In case you entered carbs but AAPS cannot see their estimated absorption through BG deviations, it will use the min_5m_carbimpact method to calculate the absorption instead (so called ‚fallback‘). Protože tato metoda počítá pouze minimální absorbci sacharidů, aniž by zvážila odchylky glykémií, může to vést k chybným hodnotám COB.

Pokyn pro chybnou hodnotu COB

In the screenshot above, 41% of time the carb absorption was mathematically calculated by the min_5m_carbimpact instead of the value detected from deviations. To znamená, že možná máte méně zbývajících sacharidů, než vypočteno.

Jak se vypořádat s tímto varováním?

  • Consider to cancel the treatment - press Cancel instead of OK.

  • Calculate your upcoming meal again with bolus wizard leaving COB unticked.

  • In case you are sure you need a correction bolus, enter it manually.

  • In any case be careful not to overdose!

Proč algoritmus nedetekuje COB správně?

  • Maybe you overestimated carbs when entering them.

  • Activity / exercise after your previous meal

  • I:C needs adjustment

  • Value for min_5m_carbimpact is wrong (recommended is 8 with SMB, 3 with AMA)

Ruční korekce zadaných sacharidů

If you over- or underestimated carbs you can correct this though treatments tab and actions tab / menu as described here.