Diabetes mellitus type 1 laboratory findings

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Case #1

Diabetes mellitus Main page
Patient Information Type 1 Type 2
Overview
Classification Diabetes mellitus type 1 Diabetes mellitus type 2 Gestational diabetes
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Vishal Devarkonda, M.B.B.S[2]

Overview

Laboratory findings consistent with the diagnosis of type 1 DM include FPG ≥126 mg/dL (7.0 mmol/L), or 2-h PG ≥200 mg/dL (11.1 mmol/L) during an OGTT, or A1C ≥6.5% (48 mmol/mol), or classic symptoms of hyperglycemia or hyperglycemic crisis, a random plasma glucose ≥200 mg/dL (11.1 mmol/L).

Laboratory Findings

Laboratory findings consistent with the diagnosis of type 1 DM include:

ADA Criteria for the diagnosis of diabetes
FPG ≥126 mg/dL (7.0 mmol/L). Fasting is defined as no caloric intake for at least 8 h.*
OR
2-h PG ≥200 mg/dL (11.1 mmol/L) during an OGTT. The test should be performed as described by the WHO, using a glucose load containing the equivalent of 75 g anhydrous glucose dissolved in water.*
OR
A1C ≥6.5% (48 mmol/mol). The test should be performed in a laboratory using a method that is NGSP certified and standardized to the DCCT assay.*
OR
In a patient with classic symptoms of hyperglycemia or hyperglycemic crisis, a random plasma glucose ≥200 mg/dL (11.1 mmol/L).

↵* In the absence of unequivocal hyperglycemia, results should be confirmed by repeat testing.

Laboratory findings in type 1 diabetes based on presentation
		Classic new onset	Diabetic Ketoacidosis
Blood	Glucose	Random: random (nonfasting) plasma glucose concentration of 200 mg/dL or higher Fasting plasma glucose concentration of 126 mg/dL (6.99 mmol/L) or higher	Random glucose level is more then 250 mg/dl
	HbA1C	HbA1c level of 6.5% or higher	Not applicable
	C-Peptide below	below 5 µU/mL	Not applicable
	Islet-cell (IA2)	Measurements of IA2 autoantibodies within 6 months of diagnosis can help differentiate between type 1 and type 2 DM	Not applicable
	Anti-GAD65	Usually present	Not applicable
	Anti-insulin autoantibodies	Usually present	Not applicable
	CBC with differential	Normal	Mildly elevated with normal differential
	Basic metabolic panel	Normal	Serum bicarbonate < 18 mEq/L Serum Sodium: Often normal or elevated Serum Phosphate: Often normal or elevated Serum Potassium: Often normal or elevated
	Serum Creatinine	Normal	Often elevated
	Serum calicum	Normal	Decreased
	Serum amylase	Normal	Mildly elevated
	Serum Lipase	Normal	Normal
	Serum osmorality	Normal	Normal
	Serum Ketones	Normal	High
	Anion gap	normal	High
	Arterial Blood gas	Normal	Metabolic acidosis, compensated by respiratory alkalosis
Urine	Glucose	May or may not be present, (blood glucose should be more then 200 mg/dl to appear in urine)	Often present
	Ketones	absent	Present

                                           
                                           FPG                          OGTT

• IA2, GAD65 and insulin autoantibodies have been detected numerous months or years before the type 1 diabetes mellitus onset. This fact leads to the idea of using these autoantibodies as predictive tools for individuals at risk of developing clinical disease. Chance of developing type 1 diabetes mellitus within 5 years was ∼10%, ∼50% and 60–80% in the presence of one, two or three autoantibodies respectively, based on one study.