Interpretation Reference ranges for blood tests

1 interpretation

1.1 plasma or whole blood
1.2 units
1.3 arterial or venous
1.4 usual or optimal
1.5 variability

interpretation

a reference range defined set of values 95 percent of normal population falls within (that is, 95% prediction interval). determined collecting data vast numbers of laboratory tests.

plasma or whole blood

in article, values (except ones listed below) denote blood plasma concentration, approximately 60–100% larger actual blood concentration if amount inside red blood cells (rbcs) negligible. precise factor depends on hematocrit amount inside rbcs. exceptions values denote total blood concentration, , in article are:

all values in hematology – red blood cells (except hemoglobin in plasma)
all values in hematology – white blood cells
platelet count (plt)

a few values inside red blood cells only:

vitamin b9 (folic acid/folate) in red blood cells
mean corpuscular hemoglobin concentration (mchc)

units

mass concentration (g/dl or g/l) common measurement unit in united states. given dl (decilitres) denominator in united states, , l (litres) in, example, sweden.
molar concentration (mol/l) used higher degree in of rest of world, including united kingdom , other parts of europe , australia , new zealand.
international units (iu) based on measured biological activity or effect, or substances, specified equivalent mass.
enzyme activity (kat) commonly used e.g. liver function tests ast, alt, ld , γ-gt in sweden.
percentages , time-dependent units (mol/s) used calculated derived parameters, e.g. beta cell function in homeostasis model assessment or thyroid s secretory capacity.

arterial or venous

if not otherwise specified, reference range blood test venous range, standard process of obtaining sample venipuncture. exception acid-base , blood gases, given arterial blood.

still, blood values approximately equal between arterial , venous sides substances, exception of acid-base, blood gases , drugs (used in therapeutic drug monitoring (tdm) assays). arterial levels drugs higher venous levels because of extraction while passing through tissues.

usual or optimal

reference ranges given usual (or normal) values found in population, more prediction interval 95% of population fall into. may called standard range. in contrast, optimal (health) range or therapeutic target reference range or limit based on concentrations or levels associated optimal health or minimal risk of related complications , diseases. substances presented, optimal levels ones found in population well. more specifically, optimal levels close central tendency of values found in population. however, usual , optimal levels may differ substantially, notably among vitamins , blood lipids, these tables give limits on both standard , optimal (or target) ranges.

in addition, values, including troponin , brain natriuretic peptide, given estimated appropriate cutoffs distinguish healthy people specific conditions, here myocardial infarction , congestive heart failure, respectively, aforementioned substances.

variability

references range may vary age, sex, race, pregnancy, diet, use of prescribed or herbal drugs , stress. reference ranges depend on analytical method used, reasons such inaccuracy, lack of standardisation, lack of certified reference material , differing antibody reactivity. also, reference ranges may inaccurate when reference groups used establish ranges small.