Common Laboratory (LAB) Values [ G ]

< G >

Lab (Specimen)

Conventional Units

SI Units

Gastrin (serum)

< 200 pg/mL (nonfasting)
< 100 pg/mL (fasting)

< 200 ng/L (nonfasting)
< 100 ng/L (fasting)

Glucagon (Serum)

50 - 200 pg/mL

50 - 200 ng/L

Glucose (fasting) plasma

< 110 mg/dL

< 6.1 mmol/L

Glucose (ADA goals)

Blood sample drawn from a vein (a whole-blood sample)
Before meals (fasting)	80 mg/dL to 120 mg/dL
Bedtime:	100 mg/dL to 140 mg/dL
Blood sample drawn from a fingertip (plasma blood sample)
Before meals (fasting)	90 mg/dL to 130 mg/dL
Bedtime:	110 mg/dL to 150 mg/dL
Less than 180 mg/dL one to two hours after meals. The ADA also recommends a hemoglobin A1c (HbA1c) target level of less than 7%.

Glucose-6-phosphate dehyrogenase (G6PD) (Blood)

5 - 13 U/g Hb

Glucose tolerance test (GTT) Plasma

Fasting Blood Glucose
From 70 to 99 mg/dL (3.9 to 5.5 mmol/L)	Normal glucose tolerance
From 100 to 125 mg/dL (5.6 to 6.9 mmol/L)	Impaired fasting glucose (pre-diabetes)
> /= 126 mg/dL (7.0 mmol/L) on more than one testing occasion	Diabetes

Oral Glucose Tolerance Test (OGTT) [except pregnancy] (2 hours after a 75-gram glucose drink)
Less than 140 mg/dL (7.8 mmol/L)	Normal glucose tolerance
From 140 to 200 mg/dL (7.8 to 11.1 mmol/L)	Impaired glucose tolerance (pre-diabetes)
Over 200 mg/dL (11.1 mmol/L) on more than one testing occasion	Diabetes

Gestational Diabetes Screening: Glucose Challenge Test (1 hour after a 50-gram glucose drink)
Less than 140* mg/dL (7.8 mmol/L)	Normal glucose tolerance
140* mg/dL (7.8 mmol/L) and over	Abnormal, needs OGTT (see below)
* Some use a cutoff of >130 mg/dL (7.2 mmol/L) because that identifies 90% of women with gestational diabetes, compared to 80% identified using the threshold of >140 mg/dL (7.8 mmol/L).

Gestational Diabetes Diagnostic: OGTT (100-gram glucose drink)
Fasting*	95 mg/dL (5.3 mmol/L)
1 hour after glucose load*	180 mg/dL (10.0 mmol/L)
2 hours after glucose load*	155 mg/dL (8.6 mmol/L)
3 hours after glucose load* **	140 mg/dL (7.8 mmol/L)
* If two or more values are above the criteria, gestational diabetes is diagnosed. ** A 75-gram glucose load may be used, although this method is not as well validated as the 100-gram OGTT; the 3-hour sample is not drawn if 75 grams is used.

Gamma Glutamyl Transferase, Serum (GTT)

Male: 8-61 U/L (< 65 U/L)
Female 5-36 U/L (< 45 U/L)

Growth Hormone (serum) GH

< 8 ng/mL

< 8 µg/L

Important Notes

>Unless noted, all values are for adults.
>All laboratory values listed are method dependent (Methods include: immunoassay, colorimetry, electrophoresis, HPLC, etc).
>Values may vary between laboratories.