export function calculateAgeBasedPediatricBloodPressureReferenceCharts(input) { const { sex, ageYearsDecimal, height, heightUnit = "cm", systolic, diastolic } = input || {}; if ( sex == null || ageYearsDecimal == null || height == null || systolic == null || diastolic == null ) { return null; } const age = Number(ageYearsDecimal); const heightNum = Number(height); const systolicNum = Number(systolic); const diastolicNum = Number(diastolic); if ( !["male", "female"].includes(sex) || !Number.isFinite(age) || !Number.isFinite(heightNum) || !Number.isFinite(systolicNum) || !Number.isFinite(diastolicNum) || age < 1 || age > 17 || heightNum <= 0 || systolicNum <= 0 || diastolicNum <= 0 ) { return null; } const heightCm = heightUnit === "in" ? heightNum * 2.54 : heightNum; const ageLower = Math.max(1, Math.floor(age)); const ageUpper = Math.min(17, Math.ceil(age)); const ageFraction = ageUpper === ageLower ? 0 : (age - ageLower) / (ageUpper - ageLower); const lowerRow = BP_DATA[sex][ageLower]; const upperRow = BP_DATA[sex][ageUpper]; if (!lowerRow || !upperRow) { return null; } const interpolated = { heights: interpolateArray(lowerRow.heights, upperRow.heights, ageFraction), sbp90: interpolateArray(lowerRow.sbp90, upperRow.sbp90, ageFraction), sbp95: interpolateArray(lowerRow.sbp95, upperRow.sbp95, ageFraction), dbp90: interpolateArray(lowerRow.dbp90, upperRow.dbp90, ageFraction), dbp95: interpolateArray(lowerRow.dbp95, upperRow.dbp95, ageFraction) }; const minAllowedHeight = interpolated.heights[0]; const maxAllowedHeight = interpolated.heights[interpolated.heights.length - 1]; const heightInReferenceRange = heightCm >= minAllowedHeight && heightCm <= maxAllowedHeight; let category; if (age >= 13) { category = classifyAbsolute(age, systolicNum, diastolicNum); } else if (!heightInReferenceRange) { // Reference-style fallback for implausible out-of-range heights: // avoid forcing percentile misclassification outside the source table domain. category = classifyAbsolute(age, systolicNum, diastolicNum); } else { const heightPercentile = estimateHeightPercentile(heightCm, interpolated.heights); const sbp90 = interpolateByPercentile(heightPercentile, HEIGHT_PERCENTILES, interpolated.sbp90); const sbp95 = interpolateByPercentile(heightPercentile, HEIGHT_PERCENTILES, interpolated.sbp95); const dbp90 = interpolateByPercentile(heightPercentile, HEIGHT_PERCENTILES, interpolated.dbp90); const dbp95 = interpolateByPercentile(heightPercentile, HEIGHT_PERCENTILES, interpolated.dbp95); category = classifyPercentileChild(systolicNum, diastolicNum, sbp90, sbp95, dbp90, dbp95); } return { "": `Age-based Pediatric Blood Pressure Reference Calculator: ${category}.` }; } const HEIGHT_PERCENTILES = [5, 10, 25, 50, 75, 90, 95]; function interpolateArray(a, b, fraction) { return a.map((value, index) => value + ((b[index] - value) * fraction)); } function interpolateByPercentile(target, percentiles, values) { if (target <= percentiles[0]) { return values[0]; } if (target >= percentiles[percentiles.length - 1]) { return values[values.length - 1]; } for (let i = 0; i < percentiles.length - 1; i += 1) { const p1 = percentiles[i]; const p2 = percentiles[i + 1]; const v1 = values[i]; const v2 = values[i + 1]; if (target >= p1 && target <= p2) { const fraction = (target - p1) / (p2 - p1); return v1 + ((v2 - v1) * fraction); } } return values[values.length - 1]; } function estimateHeightPercentile(heightCm, heights) { if (heightCm <= heights[0]) { return 5; } if (heightCm >= heights[heights.length - 1]) { return 95; } for (let i = 0; i < heights.length - 1; i += 1) { const h1 = heights[i]; const h2 = heights[i + 1]; const p1 = HEIGHT_PERCENTILES[i]; const p2 = HEIGHT_PERCENTILES[i + 1]; if (heightCm >= h1 && heightCm <= h2) { const fraction = (heightCm - h1) / (h2 - h1); return p1 + ((p2 - p1) * fraction); } } return 50; } function classifyPercentileChild(systolic, diastolic, sbp90, sbp95, dbp90, dbp95) { const sbpStage2 = Math.min(sbp95 + 12, 140); const dbpStage2 = Math.min(dbp95 + 12, 90); if (systolic >= sbpStage2 || diastolic >= dbpStage2) { return "Stage 2 HTN"; } if (systolic >= sbp95 || diastolic >= dbp95) { return "Stage 1 HTN"; } if (systolic >= sbp90 || diastolic >= dbp90) { return "Elevated BP"; } return "Normal BP"; } function classifyAbsolute(age, systolic, diastolic) { if (systolic >= 140 || diastolic >= 90) { return "Stage 2 HTN"; } if (systolic >= 130 || diastolic >= 80) { return "Stage 1 HTN"; } if (systolic >= 120 && systolic < 130 && diastolic < 80) { return "Elevated BP"; } return "Normal BP"; } const BP_DATA = { male: { 1: { heights: [77.2, 78.3, 80.2, 82.4, 84.6, 86.7, 87.9], sbp90: [98, 99, 99, 100, 100, 101, 101], sbp95: [102, 102, 103, 103, 104, 105, 105], dbp90: [52, 52, 53, 53, 54, 54, 54], dbp95: [54, 54, 55, 55, 56, 57, 57] }, 2: { heights: [86.1, 87.4, 89.6, 92.1, 94.7, 97.1, 98.5], sbp90: [100, 100, 101, 102, 103, 103, 104], sbp95: [104, 105, 105, 106, 107, 107, 108], dbp90: [55, 55, 56, 56, 57, 58, 58], dbp95: [57, 58, 58, 59, 60, 61, 61] }, 3: { heights: [92.5, 93.9, 96.3, 99.0, 101.8, 104.3, 105.8], sbp90: [101, 102, 102, 103, 104, 105, 105], sbp95: [106, 106, 107, 107, 108, 109, 109], dbp90: [58, 58, 59, 59, 60, 61, 61], dbp95: [60, 61, 61, 62, 63, 64, 64] }, 4: { heights: [98.5, 100.2, 102.9, 105.9, 108.9, 111.5, 113.2], sbp90: [102, 103, 104, 105, 105, 106, 107], sbp95: [107, 107, 108, 108, 109, 110, 110], dbp90: [60, 61, 62, 62, 63, 64, 64], dbp95: [63, 64, 65, 66, 67, 67, 68] }, 5: { heights: [104.4, 106.2, 109.1, 112.4, 115.7, 118.6, 120.3], sbp90: [103, 104, 105, 106, 107, 108, 108], sbp95: [107, 108, 109, 109, 110, 111, 112], dbp90: [63, 64, 65, 65, 66, 67, 67], dbp95: [66, 67, 68, 69, 70, 70, 71] }, 6: { heights: [110.3, 112.2, 115.3, 118.9, 122.4, 125.6, 127.5], sbp90: [105, 105, 106, 107, 109, 110, 110], sbp95: [108, 109, 110, 111, 112, 113, 114], dbp90: [66, 66, 67, 68, 68, 69, 69], dbp95: [69, 70, 70, 71, 72, 72, 73] }, 7: { heights: [116.1, 118.0, 121.4, 125.1, 128.9, 132.4, 134.5], sbp90: [106, 107, 108, 109, 110, 111, 111], sbp95: [110, 110, 111, 112, 114, 115, 116], dbp90: [68, 68, 69, 70, 70, 71, 71], dbp95: [71, 71, 72, 73, 73, 74, 74] }, 8: { heights: [121.4, 123.5, 127.0, 131.0, 135.1, 138.8, 141.0], sbp90: [107, 108, 109, 110, 111, 112, 112], sbp95: [111, 112, 112, 114, 115, 116, 117], dbp90: [69, 70, 70, 71, 72, 72, 73], dbp95: [72, 73, 73, 74, 75, 75, 75] }, 9: { heights: [126.0, 128.3, 132.1, 136.3, 140.7, 144.7, 147.1], sbp90: [107, 108, 109, 110, 112, 113, 114], sbp95: [112, 112, 113, 115, 116, 118, 119], dbp90: [70, 71, 72, 73, 74, 74, 74], dbp95: [74, 74, 75, 76, 76, 77, 77] }, 10: { heights: [130.2, 132.7, 136.7, 141.3, 145.9, 150.1, 152.7], sbp90: [108, 109, 111, 112, 113, 115, 116], sbp95: [112, 113, 114, 116, 118, 120, 121], dbp90: [72, 73, 74, 74, 75, 75, 76], dbp95: [76, 76, 77, 77, 78, 78, 78] }, 11: { heights: [134.7, 137.3, 141.5, 146.4, 151.3, 155.8, 158.6], sbp90: [110, 111, 112, 114, 116, 117, 118], sbp95: [114, 114, 116, 118, 120, 123, 124], dbp90: [74, 74, 75, 75, 75, 76, 76], dbp95: [77, 78, 78, 78, 78, 78, 78] }, 12: { heights: [140.3, 143.0, 147.5, 152.7, 157.9, 162.6, 165.5], sbp90: [113, 114, 115, 117, 119, 121, 122], sbp95: [116, 117, 118, 121, 124, 126, 128], dbp90: [75, 75, 75, 75, 75, 76, 76], dbp95: [78, 78, 78, 78, 78, 79, 79] }, 13: { heights: [147.0, 150.0, 154.9, 160.3, 165.7, 170.5, 173.4], sbp90: [115, 116, 118, 121, 124, 126, 126], sbp95: [119, 120, 122, 125, 128, 130, 131], dbp90: [74, 74, 74, 75, 76, 77, 77], dbp95: [78, 78, 78, 78, 80, 81, 81] }, 14: { heights: [153.8, 156.9, 162.0, 167.5, 172.7, 177.4, 180.1], sbp90: [119, 120, 123, 126, 127, 128, 129], sbp95: [123, 125, 127, 130, 132, 133, 134], dbp90: [74, 74, 75, 77, 78, 79, 80], dbp95: [77, 78, 79, 81, 82, 83, 84] }, 15: { heights: [159.0, 162.0, 166.9, 172.2, 177.2, 181.6, 184.2], sbp90: [123, 124, 126, 128, 129, 130, 130], sbp95: [127, 129, 131, 132, 134, 135, 135], dbp90: [75, 76, 78, 79, 80, 81, 81], dbp95: [78, 79, 81, 83, 84, 85, 85] }, 16: { heights: [162.1, 165.0, 169.6, 174.6, 179.5, 183.8, 186.4], sbp90: [126, 127, 128, 129, 131, 131, 132], sbp95: [130, 131, 133, 134, 135, 136, 137], dbp90: [77, 78, 79, 80, 81, 82, 82], dbp95: [80, 81, 83, 84, 85, 86, 86] }, 17: { heights: [163.8, 166.5, 170.9, 175.8, 180.7, 184.9, 187.5], sbp90: [128, 129, 130, 131, 132, 133, 134], sbp95: [132, 133, 134, 135, 137, 138, 138], dbp90: [78, 79, 80, 81, 82, 82, 83], dbp95: [81, 82, 84, 85, 86, 86, 87] } }, female: { 1: { heights: [75.4, 76.6, 78.6, 80.8, 83.0, 84.9, 86.1], sbp90: [98, 99, 99, 100, 101, 102, 102], sbp95: [101, 102, 102, 103, 104, 105, 105], dbp90: [54, 55, 56, 56, 57, 58, 58], dbp95: [59, 59, 60, 60, 61, 62, 62] }, 2: { heights: [84.9, 86.3, 88.6, 91.1, 93.7, 96.0, 97.4], sbp90: [101, 101, 102, 103, 104, 105, 106], sbp95: [104, 105, 106, 106, 107, 108, 109], dbp90: [58, 58, 59, 60, 61, 62, 62], dbp95: [62, 63, 63, 64, 65, 66, 66] }, 3: { heights: [91.0, 92.4, 94.9, 97.6, 100.5, 103.1, 104.6], sbp90: [102, 103, 104, 104, 105, 106, 107], sbp95: [106, 106, 107, 108, 109, 110, 110], dbp90: [60, 61, 61, 62, 63, 64, 65], dbp95: [64, 65, 65, 66, 67, 68, 69] }, 4: { heights: [97.2, 98.8, 101.4, 104.5, 107.6, 110.5, 112.2], sbp90: [103, 104, 105, 106, 107, 108, 108], sbp95: [107, 108, 109, 109, 110, 111, 112], dbp90: [62, 63, 64, 65, 66, 67, 67], dbp95: [66, 67, 68, 69, 70, 70, 71] }, 5: { heights: [103.6, 105.3, 108.2, 111.5, 114.9, 118.1, 120.0], sbp90: [104, 105, 106, 107, 108, 109, 110], sbp95: [108, 109, 109, 110, 111, 112, 113], dbp90: [64, 65, 66, 67, 68, 69, 70], dbp95: [68, 69, 70, 71, 72, 73, 73] }, 6: { heights: [110.0, 111.8, 114.9, 118.4, 122.1, 125.6, 127.7], sbp90: [105, 106, 107, 108, 109, 110, 111], sbp95: [109, 109, 110, 111, 112, 113, 114], dbp90: [67, 67, 68, 69, 70, 71, 71], dbp95: [70, 71, 72, 72, 73, 74, 74] }, 7: { heights: [115.9, 117.8, 121.1, 124.9, 128.8, 132.5, 134.7], sbp90: [106, 106, 107, 109, 110, 111, 112], sbp95: [109, 110, 111, 112, 113, 114, 115], dbp90: [68, 68, 69, 70, 71, 72, 72], dbp95: [72, 72, 73, 73, 74, 74, 75] }, 8: { heights: [121.0, 123.0, 126.5, 130.6, 134.7, 138.5, 140.9], sbp90: [107, 107, 108, 110, 111, 112, 113], sbp95: [110, 111, 112, 113, 115, 116, 117], dbp90: [69, 70, 71, 72, 72, 73, 73], dbp95: [72, 73, 74, 74, 75, 75, 75] }, 9: { heights: [125.3, 127.6, 131.3, 135.6, 140.1, 144.1, 146.6], sbp90: [108, 108, 109, 111, 112, 113, 114], sbp95: [112, 112, 113, 114, 116, 117, 118], dbp90: [71, 71, 72, 73, 73, 73, 73], dbp95: [74, 74, 75, 75, 75, 75, 75] }, 10: { heights: [129.7, 132.2, 136.3, 141.0, 145.8, 150.2, 152.8], sbp90: [109, 110, 111, 112, 113, 115, 116], sbp95: [113, 114, 114, 116, 117, 119, 120], dbp90: [72, 73, 73, 73, 73, 73, 73], dbp95: [75, 75, 76, 76, 76, 76, 76] }, 11: { heights: [135.6, 138.3, 142.8, 147.8, 152.8, 157.3, 160.0], sbp90: [111, 112, 113, 114, 116, 118, 120], sbp95: [115, 116, 117, 118, 120, 123, 124], dbp90: [74, 74, 74, 74, 74, 75, 75], dbp95: [76, 77, 77, 77, 77, 77, 77] }, 12: { heights: [142.8, 145.5, 149.9, 154.8, 159.6, 163.8, 166.4], sbp90: [114, 115, 116, 118, 120, 122, 122], sbp95: [118, 119, 120, 122, 124, 125, 126], dbp90: [75, 75, 75, 75, 76, 76, 76], dbp95: [78, 78, 78, 78, 79, 79, 79] }, 13: { heights: [148.1, 150.6, 154.7, 159.2, 163.7, 167.8, 170.2], sbp90: [116, 117, 119, 121, 122, 123, 123], sbp95: [121, 122, 123, 124, 126, 126, 127], dbp90: [75, 75, 75, 76, 76, 76, 76], dbp95: [79, 79, 79, 79, 80, 80, 81] }, 14: { heights: [150.6, 153.0, 156.9, 161.3, 165.7, 169.7, 172.1], sbp90: [118, 118, 120, 122, 123, 123, 123], sbp95: [123, 123, 124, 125, 126, 127, 127], dbp90: [76, 76, 76, 76, 77, 77, 77], dbp95: [80, 80, 80, 80, 81, 81, 82] }, 15: { heights: [151.7, 154.0, 157.9, 162.3, 166.7, 170.6, 173.0], sbp90: [118, 119, 121, 122, 123, 123, 124], sbp95: [124, 124, 125, 126, 127, 127, 128], dbp90: [76, 76, 76, 77, 77, 78, 78], dbp95: [80, 80, 80, 81, 82, 82, 82] }, 16: { heights: [152.1, 154.5, 158.4, 162.8, 167.1, 171.1, 173.4], sbp90: [119, 120, 122, 123, 124, 124, 124], sbp95: [124, 125, 125, 127, 127, 128, 128], dbp90: [76, 76, 76, 77, 78, 78, 78], dbp95: [80, 80, 80, 81, 82, 82, 82] }, 17: { heights: [152.4, 154.7, 158.7, 163.0, 167.4, 171.3, 173.7], sbp90: [120, 121, 123, 124, 124, 125, 125], sbp95: [125, 125, 126, 127, 128, 128, 128], dbp90: [76, 76, 77, 77, 78, 78, 78], dbp95: [80, 80, 80, 81, 82, 82, 82] } } };