I'm not sure whether I have insufficient information from your message, or that the test has nothing to do with make-up air. So lets review.

House pressure. It matters if the kitchen hood lowers the house pressure too much. One aspect of mattering is pulling air through cracks in the walls and other leakage paths, which can affect humidity in the walls and dust in the house. A second aspect is back-drafting combustion appliances, if any, depending on type and what the pressure is; this is a carbon monoxide hazard. A third aspect is that the lower the house pressure relative to the outside where the hood blower is pushing the air, the less air that is moved by the hood blower (lower CFM). Even if aspects one and two are not issues, one needs to know what the house pressure falls by (relative to the outside) as a function of air flow out of the house. Then, the blower fan curve can be consulted (along with an estimate of the pressure loss of the hood baffles) to see how much air flow one is likely to achieve, and compare that with the air flow need of the hood for good capture and containment.

So, did the blower door test result in pressure vs. flow rate data? Do you have any combustion appliances? If so, of what type and do they have their own MUA not involving air from the kitchen?

You need MUA. It’s required, no matter what. You didn’t “pass” the test. There is no pass or fail. An air leaky house is a bad thing, not a good thing.

You failed the blower door test for new construction in many jurisdiction by a lot. Over ten times the allowed amount. A lot. Maybe this can be a seasonal home?

Hi. I guess I should clarify my terminology and not use the word pass. The reason for the test was to determine if makeup air would be required by code should we use a hood with cfm > 400. Otherwise it would be required by code in Ohio. Because the house is leaky, the test results indicate that we do not require makeup air for the hood by code. I can ask for the pressure/flow rate data. In terms of combustible appliances, we have a furnace in the basement, washer/dryer on the second floor above the kitchen and a wood burning fireplace. I know meeting code does not necessarily mean there is no health risk which is why I'm asking the question. Also, could we use a lesser amount of MUA given the leakiness of the house? I'll try to provide more info. I just don't have a full understanding of this even after reading all the threads on here.

I think it's a dangerous game to hope that the leakiness of the house keeps you safe when using indoor combustion.

What type of fuel is used in the furnace? If gas, is it a high efficiency furnace?

Insulate and air seal your house better. And put in MUA. Your utility bills must be pretty large with that leaky of a house!

As an update, I misspoke earlier. The home has a boiler and not a furnace so I would think less an issue. With regards to insulation and air sealing, it's a 100 year old home with original windows which are beautiful so while it's not energy saving we don't have plans to change that.

A remarkable failure to answer a simple question with unambiguous information. If I assume that the OP is referring to an BLOWN OIL-FIRED BOILER that uses household air, then it can back-draft at perhaps as high 0.08 inches of water (20 Pa) negative pressure, depending on chimney leakage, but I wouldn't want to depend on that. I don't doubt that at some hood volumetric flow rate, back-drafting can occur even in a leaky house. Perhaps in this case it won't. Approaching 0.08 inches, w.c., is significant relative to hood blowers, however, so along with the baffles and duct pressure losses, there will be additional pressure loss from the leakage MUA affecting flow rate.

If this were my house, I would (and did) install an MUA system for the furnace, which are typically passive and use 4-inch duct. These are made for common oil burner assemblies. Boiler MUA will avoid back-drafting at the intake, but there may be exhaust leakage from the chimney (old masonry chimneys are not truly sealed unless updated with internal ducting), or even from the flue test port.

Then there is the dryer, presumably gas fired and minimally if at all blown. This will have a much lower threshold of back-drafting than an oil burner, perhaps 0.01 inches.

Fireplaces have a very low back-draft threshold depending on the induced draft from a hot fire. Starting a fire under negative pressure conditions could be challenging.

All of this ignores what flow rate is appropriate for the actual cooking surface and a hood sized to overlap it. A proper hood 4.5 ft x 2 ft would have an entry area of 9 sq. ft. requiring 810 CFM for good performance. This would potentially be available from a 1200 CFM rated blower, given likely baffle, duct, and house negative pressure losses.

So the question still unanswered is what CFM led to what house pressure using the door test?