Let’s look at an example of a death due to COVID-19.

“A 58-year-old male patient, known with a past medical history of hypertension and type 2 diabetes, since age 38, presented with a 1-week history of anosmia, cough and myalgia, and a 3-day history of dyspnoea.  In hospital he deteriorated over the course of 3 days, was diagnosed with Acute respiratory distress syndrome and admitted to the ICU.  His COVID swab from admission at this point, returned positive.  In ICU, his respiratory status continued to deteriorate.  He died 2 days later. 

In this case,

•The immediate cause of death is Acute respiratory distress syndrome, reported in Part 1, line a.
•The diagnosis of COVID-19 is confirmed with laboratory testing and is clearly the underlying cause of death, so it reported on the lowest used line of Part 1. 
•The chronic pre-existing illnesses of diabetes and hypertension are considered to have contributed to the death but since they do not form part of the causal sequence reported in Part 1, they are reported in Part 2 as contributing conditions.