Cálculo 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.

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.


Los carbohidratos no absorbidos se cortan después del tiempo especificado


AAPS, promedio ponderado

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

AAPS, Promedio ponderado

Si se utiliza la absorción mínima de carbohidratos (min_5m_carbimpact) en lugar del valor calculado a partir de las desviaciones de BG, aparece un punto naranja en el gráfico COB.

Detección de valores COB incorrectos

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. En este caso, le dará una sugerencia adicional en la pantalla de confirmación después del uso del asistente en bolo.

How does AAPS detect wrong COB values?

Normalmente, AAPS detecta la absorción de carbohidros a través de desviaciones de BG. 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”). Como este método calcula sólo la absorción mínima de carbohidratos sin considerar desviaciones de BG, podría llevar a valores de COB incorrectos.

Pista de un valor COB incorrecto

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. Esto significa que tal vez tenga menos carbohidratos a bordo que los calculados por el algoritmo.

¿Cómo hacer frente a esta advertencia?

  • 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!

¿Por qué el algoritmo no detecta correctamente el COB?

  • 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)

Corrección manual de los carbohidratos ingresados

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