Blood test

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High blood sugar/glucose level

Blood test
High blood sugar/glucose level
Last update: 02/04/2020

What is high glucose/sugar level in the blood called?

  • Hyperglycemia

What is the normal level of blood sugar/glucose?

If you need to know which are the sugar/glucose reference ranges or you require more information about the role of sugar/glucose in the blood, you can visit normal sugar/glucose level in the blood

What does high blood sugar/glucose levels mean?

Hyperglycemia (high glucose/sugar level in blood) usually means that the pancreas does not produce enough insulin, or the insulin produced by it does not function properly (insulin resistance).

Blood sugar values are usually given in mg/dl but sometimes you can see those values in mmol/l following the International System of Units (SI). In case your values are in mmol/l you can convert them using this tool:

  • Mild hyperglycemia (100 – 126 mg/dl in adults):

    Mild hyperglycemia is not usually a cause for concern. You may have prediabetes. In prediabetes, blood sugar level is slightly higher than normal, but still not as high as in diabetes. That means that you are more likely to develop diabetes in a near future.

    You should take care of your health doing regular physical activity and following a diet plan. It is advisable to take a new blood test a few months later to see if your level is within the normal range.

  • Moderate hyperglycemia (126 – 250 mg/dl in adults):

    Your blood sugar/glucose level is abnormally high and you probably have diabetes.

    For this reason, you need medical follow-up. The most common specialists in the field of diabetes are endocrinologists. You would be advised to lose weight with a healthy meal plan. In case your values keep on high in the following blood test, your doctor may recommend anti-diabetic medication and insulin therapy.

    You can read the diabetic diagnosis criteria in the annex 1.

  • Marked hyperglycemia (250 - 400 mg/dl in adults):

    Your blood sugar/glucose level is too high and it is a matter of concern.

    You probably have diabetes and you must visit an endocrinologist as soon as possible to start a treatment for diabetes with oral anti-diabetic drugs or insulin. If you are already under treatment, your doctor should adjust the insulin dose.

  • Severe hyperglycemia (> 400 mg/dl in adults):

    Your blood sugar/glucose level is so high that you should be feeling excessive thirst (polydipsia) and the need to urinate more often (polyuria). It can also cause confusion and other changes in mental status.

    Your blood sugar/glucose is so high that it can lead to a diabetic coma that requires urgent medical care.

Which factors can raise your blood sugar/glucose level?

There are some health situations or drugs than can raise your blood sugar/glucose level:

  • Vigorous exercise
  • Pregnancy
  • Stress
  • Infections
  • Brain damage
  • Obesity
  • Intracranial pressure
  • Severe burns
  • Drugs

Which diseases can raise your blood sugar/glucose level?

There are many medical conditions why the blood sugar/glucose level can be higher than normal:

What can I do to lower the blood sugar/glucose level?

If your blood sugar/glucose level is slightly high (100-126 gr/dl) you can consider the following tips:

  • No sugar diet.
  • Do regular, gentle exercise (walking, swimming, and cycling).

If your glucose level keeps over 125 gr/dl, you probably need antidiabetic drugs (insulin) to bring it down.

ANNEX I: Diabetes Diagnostic Criteria

The criteria for diagnosing Diabetes is the presence of at least one of the following assumptions:

  1. Hemoglobina A1C (glycoside hemoglobin) > 6.5%.
    • Standard methods
  2. Basal plasma glucose: > 126 mg/dl (7.0mmol/l).
    • 8 hours after your last meal (fasting)
  3. Glucose >200 mg/dl (11.1 mmol/l) after 75 gr oral glucose overload
  4. Hyperglycemia > 200 mg/dl (11.1 mmol/l).
* If there is no report about previous hyperglycemia points 1 and 3 must be confirmed in a new test.

Where can I find more information about the blood sugar/glucose level?

You can visit our pages about:

Which values are considered a high sugar/glucose level in the blood?

The following values are considered to be above the normal range:

IMPORTANT: These levels are expressed in mg/dl. They are an example of a healthy man of about 45 years of age with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.

Blood Sugar
Mild hyperglycemia
101 mg/dl102 mg/dl103 mg/dl104 mg/dl105 mg/dl106 mg/dl107 mg/dl108 mg/dl
109 mg/dl110 mg/dl111 mg/dl112 mg/dl113 mg/dl114 mg/dl115 mg/dl116 mg/dl
117 mg/dl118 mg/dl119 mg/dl120 mg/dl121 mg/dl122 mg/dl123 mg/dl124 mg/dl
125 mg/dl       
Moderate hyperglycemia
126 mg/dl127 mg/dl128 mg/dl129 mg/dl130 mg/dl131 mg/dl132 mg/dl133 mg/dl
134 mg/dl135 mg/dl136 mg/dl137 mg/dl138 mg/dl139 mg/dl140 mg/dl141 mg/dl
142 mg/dl143 mg/dl144 mg/dl145 mg/dl146 mg/dl147 mg/dl148 mg/dl149 mg/dl
150 mg/dl151 mg/dl152 mg/dl153 mg/dl154 mg/dl155 mg/dl156 mg/dl157 mg/dl
158 mg/dl159 mg/dl160 mg/dl161 mg/dl162 mg/dl163 mg/dl164 mg/dl165 mg/dl
166 mg/dl167 mg/dl168 mg/dl169 mg/dl170 mg/dl171 mg/dl172 mg/dl173 mg/dl
174 mg/dl175 mg/dl176 mg/dl177 mg/dl178 mg/dl179 mg/dl180 mg/dl181 mg/dl
182 mg/dl183 mg/dl184 mg/dl185 mg/dl186 mg/dl187 mg/dl188 mg/dl189 mg/dl
190 mg/dl191 mg/dl192 mg/dl193 mg/dl194 mg/dl195 mg/dl196 mg/dl197 mg/dl
198 mg/dl199 mg/dl200 mg/dl201 mg/dl202 mg/dl203 mg/dl204 mg/dl205 mg/dl
206 mg/dl207 mg/dl208 mg/dl209 mg/dl210 mg/dl211 mg/dl212 mg/dl213 mg/dl
214 mg/dl215 mg/dl216 mg/dl217 mg/dl218 mg/dl219 mg/dl220 mg/dl221 mg/dl
222 mg/dl223 mg/dl224 mg/dl225 mg/dl226 mg/dl227 mg/dl228 mg/dl229 mg/dl
230 mg/dl231 mg/dl232 mg/dl233 mg/dl234 mg/dl235 mg/dl236 mg/dl237 mg/dl
238 mg/dl239 mg/dl240 mg/dl241 mg/dl242 mg/dl243 mg/dl244 mg/dl245 mg/dl
246 mg/dl247 mg/dl248 mg/dl249 mg/dl250 mg/dl   
Marked hyperglycemia
251 mg/dl252 mg/dl253 mg/dl254 mg/dl255 mg/dl256 mg/dl257 mg/dl258 mg/dl
259 mg/dl260 mg/dl261 mg/dl262 mg/dl263 mg/dl264 mg/dl265 mg/dl266 mg/dl
267 mg/dl268 mg/dl269 mg/dl270 mg/dl271 mg/dl272 mg/dl273 mg/dl274 mg/dl
275 mg/dl276 mg/dl277 mg/dl278 mg/dl279 mg/dl280 mg/dl281 mg/dl282 mg/dl
283 mg/dl284 mg/dl285 mg/dl286 mg/dl287 mg/dl288 mg/dl289 mg/dl290 mg/dl
291 mg/dl292 mg/dl293 mg/dl294 mg/dl295 mg/dl296 mg/dl297 mg/dl298 mg/dl
299 mg/dl300 mg/dl301 mg/dl302 mg/dl303 mg/dl304 mg/dl305 mg/dl306 mg/dl
307 mg/dl308 mg/dl309 mg/dl310 mg/dl311 mg/dl312 mg/dl313 mg/dl314 mg/dl
315 mg/dl316 mg/dl317 mg/dl318 mg/dl319 mg/dl320 mg/dl321 mg/dl322 mg/dl
323 mg/dl324 mg/dl325 mg/dl326 mg/dl327 mg/dl328 mg/dl329 mg/dl330 mg/dl
331 mg/dl332 mg/dl333 mg/dl334 mg/dl335 mg/dl336 mg/dl337 mg/dl338 mg/dl
339 mg/dl340 mg/dl341 mg/dl342 mg/dl343 mg/dl344 mg/dl345 mg/dl346 mg/dl
347 mg/dl348 mg/dl349 mg/dl350 mg/dl351 mg/dl352 mg/dl353 mg/dl354 mg/dl
355 mg/dl356 mg/dl357 mg/dl358 mg/dl359 mg/dl360 mg/dl361 mg/dl362 mg/dl
363 mg/dl364 mg/dl365 mg/dl366 mg/dl367 mg/dl368 mg/dl369 mg/dl370 mg/dl
371 mg/dl372 mg/dl373 mg/dl374 mg/dl375 mg/dl376 mg/dl377 mg/dl378 mg/dl
379 mg/dl380 mg/dl381 mg/dl382 mg/dl383 mg/dl384 mg/dl385 mg/dl386 mg/dl
387 mg/dl388 mg/dl389 mg/dl390 mg/dl391 mg/dl392 mg/dl393 mg/dl394 mg/dl
395 mg/dl396 mg/dl397 mg/dl398 mg/dl399 mg/dl400 mg/dl  
Severe hyperglycemia
401 mg/dl402 mg/dl403 mg/dl404 mg/dl405 mg/dl406 mg/dl407 mg/dl408 mg/dl
409 mg/dl410 mg/dl411 mg/dl412 mg/dl413 mg/dl414 mg/dl415 mg/dl416 mg/dl
417 mg/dl418 mg/dl419 mg/dl420 mg/dl421 mg/dl422 mg/dl423 mg/dl424 mg/dl
425 mg/dl426 mg/dl427 mg/dl428 mg/dl429 mg/dl430 mg/dl431 mg/dl432 mg/dl
433 mg/dl434 mg/dl435 mg/dl436 mg/dl437 mg/dl438 mg/dl439 mg/dl440 mg/dl
441 mg/dl442 mg/dl443 mg/dl444 mg/dl445 mg/dl446 mg/dl447 mg/dl448 mg/dl
449 mg/dl450 mg/dl451 mg/dl452 mg/dl453 mg/dl454 mg/dl455 mg/dl456 mg/dl
457 mg/dl458 mg/dl459 mg/dl460 mg/dl461 mg/dl462 mg/dl463 mg/dl464 mg/dl
465 mg/dl466 mg/dl467 mg/dl468 mg/dl469 mg/dl470 mg/dl471 mg/dl472 mg/dl
473 mg/dl474 mg/dl475 mg/dl476 mg/dl477 mg/dl478 mg/dl479 mg/dl480 mg/dl
481 mg/dl482 mg/dl483 mg/dl484 mg/dl485 mg/dl486 mg/dl487 mg/dl488 mg/dl
489 mg/dl490 mg/dl491 mg/dl492 mg/dl493 mg/dl494 mg/dl495 mg/dl496 mg/dl
497 mg/dl498 mg/dl499 mg/dl500 mg/dl501 mg/dl502 mg/dl503 mg/dl504 mg/dl
505 mg/dl506 mg/dl507 mg/dl508 mg/dl509 mg/dl510 mg/dl511 mg/dl512 mg/dl
513 mg/dl514 mg/dl515 mg/dl516 mg/dl517 mg/dl518 mg/dl519 mg/dl520 mg/dl
521 mg/dl522 mg/dl523 mg/dl524 mg/dl525 mg/dl526 mg/dl527 mg/dl528 mg/dl
529 mg/dl530 mg/dl531 mg/dl532 mg/dl533 mg/dl534 mg/dl535 mg/dl536 mg/dl
537 mg/dl538 mg/dl539 mg/dl540 mg/dl541 mg/dl542 mg/dl543 mg/dl544 mg/dl
545 mg/dl546 mg/dl547 mg/dl548 mg/dl549 mg/dl550 mg/dl551 mg/dl552 mg/dl
553 mg/dl554 mg/dl555 mg/dl556 mg/dl557 mg/dl558 mg/dl559 mg/dl560 mg/dl
561 mg/dl562 mg/dl563 mg/dl564 mg/dl565 mg/dl566 mg/dl567 mg/dl568 mg/dl
569 mg/dl570 mg/dl571 mg/dl572 mg/dl573 mg/dl574 mg/dl575 mg/dl576 mg/dl
577 mg/dl578 mg/dl579 mg/dl580 mg/dl581 mg/dl582 mg/dl583 mg/dl584 mg/dl
585 mg/dl586 mg/dl587 mg/dl588 mg/dl589 mg/dl590 mg/dl591 mg/dl592 mg/dl
593 mg/dl594 mg/dl595 mg/dl596 mg/dl597 mg/dl598 mg/dl599 mg/dl600 mg/dl
601 mg/dl602 mg/dl603 mg/dl604 mg/dl605 mg/dl606 mg/dl607 mg/dl608 mg/dl
609 mg/dl610 mg/dl611 mg/dl612 mg/dl613 mg/dl614 mg/dl615 mg/dl616 mg/dl
617 mg/dl618 mg/dl619 mg/dl620 mg/dl621 mg/dl622 mg/dl623 mg/dl624 mg/dl
625 mg/dl626 mg/dl627 mg/dl628 mg/dl629 mg/dl630 mg/dl631 mg/dl632 mg/dl
Medically reviewed by Javier Muga Bustamante Ph.D. on 02/04/2020


  • Concise Book of Medical Laboratory Technology: Methods and Interpretations. 2nd Edition. 2015. Ramnik Sood. ISBN: 978-93-5152-333-8. Pag. 490.
  • Diabetes Care Volume 37, Supplement 1, January 2014.
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