Pernicious Anemia: Likelihood Ratios

Introduction: Autoimmune attack of the parietal cells in the stomach that are responsible for producing intrinsic factor. Intrinsic factor is necessary for the absorption of vitamin B12 (cobalamin), thus its loss causes Megaloblastic Anemia.

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The likelihood ratios of findings for Pernicious Anemia are listed below. See the left navigation bar to change the display.

Good Positive and Negative Likelihood Ratios

Finding	+LR	-LR	Comments, Study
Anti-parietal Cell Antibody	8.5	0.2	Study: Arch Intern Med. 1999 Jun 28;159(12):1289-98. PMID: 10386505

Poorly Diagnostic Findings

Finding	+LR	-LR	Comments, Study
Elevated Fasting Serum Gastrin	Sensitivity = 90%		>200ng/L. Specificity not assessed. Study: Arch Intern Med. 1999 Jun 28;159(12):1289-98. PMID: 10386505 Am J Clin Pathol. 1988 Oct;90(4):442-5. PMID: 3177265
Anti-Intrinsic Factor Antibodies	Sensitivity = 50%		Specificity not mentioned but given as "rarely present in healthy individuals". Some people with Graves + anti-IF may progress to pernicious anemia. Study: Arch Intern Med. 1999 Jun 28;159(12):1289-98. PMID: 10386505