Table 1.2.a. Red blood cell (RBC) folate: Total population

Geometric mean and selected percentiles of RBC concentrations (in ng/mL) for the total U.S. population aged 3 years and older, National Health and Nutrition Examination Survey, 1999–2002.

Geometric mean
(95% conf. interval)

Selected percentiles (95% conf. interval)

Sample
size

5th

50th

95th

Males and Females

Total, 3 years and older

280

(273-287)

154

(149-159)

276

(270-282)

526

(510-541)

16102

3–5 years

288

(281-296)

192

(184-203)

286

(278-293)

464

(403-512)

840

6–11 years

280

(273-287)

186

(178-192)

277

(269-284)

431

(413-482)

1938

12–19 years

244

(237-251)

150

(145-155)

240

(234-246)

411

(393-436)

4362

20–39 years

255

(248-262)

142

(135-149)

252

(241-261)

452

(437-474)

3195

40–59 years

291

(283-299)

159

(151-167)

289

(282-297)

538

(500-576)

2709

60 years and older

338

(330-345)

169

(160-178)

341

(331-351)

667

(634-688)

3058

Males

Total, 3 years and older

272

(265-279)

153

(148-159)

268

(260-275)

494

(480-515)

7827

3–5 years

291

(278-304)

192

(180-206)

287

(277-300)

477

(394-559)

438

6–11 years

287

(279-295)

201

(189-209)

280

(272-288)

448

(423-504)

989

12–19 years

240

(232-249)

150

(142-159)

238

(232-245)

398

(372-436)

2179

20–39 years

246

(238-254)

146

(139-151)

245

(235-256)

418

(395-440)

1358

40–59 years

282

(274-291)

157

(148-168)

280

(271-291)

516

(481-545)

1349

60 years and older

325

(314-337)

159

(147-170)

324

(310-339)

644

(593-702)

1514

Females

Total, 3 years and older

288

(281-295)

155

(149-161)

285

(278-292)

552

(531-573)

8275

3–5 years

286

(277-295)

190

(177-201)

287

(276-293)

441

(386-519)

402

6–11 years

272

(264-280)

178

(171-185)

271

(261-281)

402

(385-469)

949

12–19 years

247

(239-255)

148

(145-155)

244

(235-251)

422

(386-476)

2183

20–39 years

264

(256-274)

140

(132-152)

261

(251-273)

492

(455-540)

1837

40–59 years

300

(288-312)

164

(151-174)

297

(285-309)

565

(505-595)

1360

60 years and older

347

(340-355)

176

(163-185)

353

(339-364)

673

(634-698)

1544

Table 1.2.b. Red blood cell (RBC) folate: Mexican Americans

Geometric mean and selected percentiles of RBC concentrations (in ng/mL) for Mexican Americans in the U.S. population aged 3 years and older, National Health and Nutrition Examination Survey, 1999–2002.

Geometric mean
(95% conf. interval)

Selected percentiles (95% conf. interval)

Sample
size

5th

50th

95th

Males and Females

Total, 3 years and older

258

(251-265)

155

(146-161)

254

(248-261)

456

(435-473)

4726

3–5 years

289

(280-298)

201

(194-210)

278

(270-289)

458

(403-524)

273

6–11 years

282

(276-288)

197

(180-211)

276

(270-282)

444

(402-492)

658

12–19 years

245

(239-252)

156

(145-164)

241

(237-248)

408

(381-428)

1642

20–39 years

239

(231-248)

140

(126-149)

235

(229-243)

423

(392-443)

870

40–59 years

273

(263-283)

167

(160-172)

267

(255-275)

496

(454-552)

634

60 years and older

301

(285-317)

161

(141-180)

291

(275-314)

590

(534-711)

649

Males

Total, 3 years and older

250

(242-258)

145

(133-155)

251

(241-257)

430

(401-457)

2306

3–5 years

297

(284-311)

210†

(196-220)

283

(270-299)

514†

(401-599)

144

6–11 years

287

(280-295)

201

(185-214)

283

(274-292)

443

(383-511)

339

12–19 years

241

(234-248)

155

(141-166)

238

(233-246)

376

(356-406)

813

20–39 years

227

(215-239)

129

(114-147)

225

(211-237)

392

(351-435)

385

40–59 years

263

(252-275)

165

(152-171)

265

(251-278)

432

(392-498)

302

60 years and older

293

(269-318)

152

(133-190)

285

(266-299)

567

(525-702)

323

Females

Total, 3 years and older

268

(260-275)

159

(155-168)

260

(251-266)

488

(457-517)

2420

3–5 years

279

(267-292)

188†

(182-203)

272

(259-289)

418†

(371-458)

129

6–11 years

276

(268-285)

194

(173-212)

268

(263-275)

434

(384-492)

319

12–19 years

250

(242-258)

157

(145-167)

243

(237-250)

434

(393-486)

829

20–39 years

255

(246-265)

152

(141-159)

250

(233-260)

436

(421-512)

485

40–59 years

284

(269-299)

171

(163-181)

269

(248-291)

538

(464-624)

332

60 years and older

308

(295-321)

168

(154-184)

305

(280-318)

600

(532-785)

326

† Estimate is subject to greater uncertainty due to small cell size.

Table 1.2.c. Red blood cell (RBC) folate: Non-Hispanic blacks

Geometric mean and selected percentiles of RBC concentrations (in ng/mL) for non-Hispanic blacks in the U.S. population aged 3 years and older, National Health and Nutrition Examination Survey, 1999–2002.

Geometric mean
(95% conf. interval)

Selected percentiles (95% conf. interval)

Sample
size

5th

50th

95th

Males and Females

Total, 3 years and older

221

(216-226)

123

(120-129)

220

(214-224)

383

(370-399)

3783

3–5 years

247

(240-254)

166

(159-180)

244

(235-251)

364

(326-411)

248

6–11 years

238

(232-243)

161

(151-172)

240

(233-247)

336

(322-350)

623

12–19 years

200

(196-205)

123

(117-129)

203

(197-209)

310

(295-320)

1265

20–39 years

209

(202-216)

117

(113-124)

209

(201-215)

361

(340-385)

598

40–59 years

222

(215-230)

120

(111-130)

222

(213-231)

396

(367-427)

553

60 years and older

254

(243-267)

125

(110-136)

255

(240-267)

535

(476-590)

496

Males

Total, 3 years and older

216

(210-222)

122

(116-132)

219

(212-226)

360

(341-372)

1856

3–5 years

246

(235-257)

168†

(145-188)

244

(234-254)

364†

(314-508)

130

6–11 years

243

(237-250)

161

(153-178)

248

(238-255)

334

(313-361)

316

12–19 years

203

(198-209)

124

(116-131)

208

(202-214)

310

(292-327)

645

20–39 years

203

(194-211)

118

(101-135)

207

(197-214)

322

(302-350)

249

40–59 years

211

(202-221)

121

(104-132)

211

(194-226)

364

(348-396)

277

60 years and older

244

(229-260)

117

(103-134)

248

(227-266)

460

(403-592)

239

Females

Total, 3 years and older

225

(219-231)

124

(117-130)

221

(216-226)

411

(378-453)

1927

3–5 years

248

(238-258)

165†

(159-181)

244

(233-258)

379†

(319-453)

118

6–11 years

232

(224-240)

158

(132-177)

230

(221-242)

336

(319-369)

307

12–19 years

197

(192-202)

124

(111-131)

197

(189-201)

303

(291-320)

620

20–39 years

214

(205-223)

119

(113-127)

210

(200-220)

379

(352-445)

349

40–59 years

233

(222-244)

122

(109-141)

233

(220-247)

409

(370-512)

276

60 years and older

262

(246-279)

127

(104-151)

262

(241-277)

553

(496-599)

257

† Estimate is subject to greater uncertainty due to small cell size.

Table 1.2.d. Red blood cell (RBC) folate: Non-Hispanic whites

Geometric mean and selected percentiles of RBC concentrations (in ng/mL) for non-Hispanic whites in the U.S. population aged 3 years and older, National Health and Nutrition Examination Survey, 1999–2002.

Geometric mean
(95% conf. interval)

Selected percentiles (95% conf. interval)

Sample
size

5th

50th

95th

Males and Females

Total, 3 years and older

297

(289-304)

166

(160-172)

292

(284-299)

551

(536-570)

6210

3–5 years

303

(289-318)

204

(180-231)

300

(290-309)

474

(390-546)

231

6–11 years

292

(283-301)

189

(183-207)

290

(282-296)

464

(422-519)

498

12–19 years

257

(249-265)

160

(152-164)

253

(246-261)

436

(400-458)

1083

20–39 years

268

(257-279)

150

(135-165)

265

(252-278)

475

(449-524)

1383

40–59 years

305

(296-313)

173

(166-180)

302

(293-309)

545

(506-597)

1291

60 years and older

352

(342-361)

182

(170-193)

355

(344-365)

674

(639-702)

1724

Males

Total, 3 years and older

287

(279-296)

165

(158-173)

281

(272-291)

523

(501-544)

3037

3–5 years

308

(286-332)

204†

(165-231)

310

(290-324)

512†

(403-634)

120

6–11 years

300

(289-311)

211

(189-225)

290

(276-299)

473

(422-533)

263

12–19 years

251

(241-261)

158

(145-164)

246

(238-256)

410

(372-454)

538

20–39 years

258

(247-269)

157

(147-165)

256

(241-270)

432

(402-463)

578

40–59 years

295

(286-304)

171

(157-180)

292

(280-303)

527

(491-601)

672

60 years and older

339

(325-355)

170

(158-190)

342

(322-359)

660

(601-717)

866

Females

Total, 3 years and older

306

(297-315)

167

(159-174)

302

(293-310)

580

(551-604)

3173

3–5 years

298

(285-311)

201†

(189-236)

294

(279-307)

436†

(382-546)

111

6–11 years

283

(273-294)

182

(173-192)

290

(277-298)

453

(381-508)

235

12–19 years

264

(253-275)

160

(149-167)

262

(250-270)

451

(395-539)

545

20–39 years

278

(265-293)

143

(130-167)

278

(261-293)

548

(490-591)

805

40–59 years

315

(300-330)

176

(165-190)

308

(295-327)

570

(503-611)

619

60 years and older

361

(354-369)

191

(182-201)

364

(351-372)

680

(639-711)

858

† Estimate is subject to greater uncertainty due to small cell size.