Students in grades seven and 11 in Maryland's public schools showed slight gains in the minimal reading skills they need to function as competent consumers and citizens, according to test results made available yesterday.

But significant numbers -- 31 per cent of the seventh graders and 13 per cent of the 11th graders -- still failed to demonstrate the minimum levels of reading competency they would need to survive as functioning adults.

The tests were administered in October to 124,000 seventh and 11th graders as part of a statewide effort to gauge how well schools are preparing students to cope in an increasingly complex society.

Among the skills tested were reading the label on a medicine bottle, understanding directions in a voting machine reading a catalogue, finding headings in an index, using a telephone directory or following instructions to fill out a form.

Students were expected to answer 80 per cent of the questions correctly in order to pass the test.

Last October the percentage of 11th graders passing the test rose to 87 per cent, up from 80 per cent the previous October--the first year the tests were given. At the seventh-grade level, the gains were less impressive--69 per cent of the students passed in October, 1976, compared to 65 per cent a year earlier.

State education officials said the improvement could possibly be accounted for by the fact that since the initial tests in October, 1975, guidelines have been developed and increased emphasis has been placed on functional reading skills.

Locally, Montgomery and Howard counties led the state, while Prince George's County students were slightly below the state average.

The Montgomery 11th graders, with a 94 per cent pass rate, were first statewide, while the seventh graders, with a pass rate of 84 per cent, were in second place. Both levels reflected an improvement of four percentage points over October, 1975.

In Howard County, the seventh graders, with a pass rate of 87 per cent, were first in the state, while the 11th graders, with a 92 per cent pass rate, were in second place.

While the Prince George's students showed gains at both the seventh-and 11th-grade levels, those gains were less than the average gains for the state as a whole and the scores were slightly below the state averages.

At the seventh-grade level, 64 per cent of the Prince George's students passed the test--a gain of two percentage points over the previous year, but still five percentage points behind the state average.

For the 11th grade, the gain was four percentage points to a pass rate of 86 per cent, one percentage point below the state average.

In a report to the Prince George's school board, County School Supt. Edward J. Feeney called the gains a "direct result of our efforts to improve the functional reading component of our instructional program."

Nevertheless, school officials in Prince George's are disturbed that the gains posted by their students were less than the average gains statewide. Beginning next fall, they said, functional reading will receive increased emphasis in Prince George's schools, and a staff team is already working to prepare new materials and guidelines for teachers.

The dominance of Montgomery and Howard counties at the top of the scale reflects a pattern that has developed in standardized achievement tests taken in the spring by third, fifth, seventh and ninth graders throughout the state.