Rapid Review II: Organ Panels, Markers, and Drug Levels
A cardiac marker time curve, hours from onset on the x axis with a compressed break to day 14, multiples of the upper reference limit on the y axis, three flat-stroke curves for myoglobin, CK-MB, and troponin I, each labeled at its peak, with a vertical amber band marking the window in which only troponin is still positive.
Strip 1 · Liver
| Value | Range |
|---|---|
| ALT | 4–36 units/L |
| AST | 0–35 units/L |
| Alkaline phosphatase | 30–120 units/L |
| Total bilirubin | 0.3–1.0 mg/dL |
| Albumin | 3.5–5.0 g/dL |
Hook: the enzymes are the injury numbers. Albumin is the synthesis number, so it tells you how long the liver has been failing, not that it was hurt this morning.
Strip 2 · Ammonia
Ammonia 15–45 mcg/dL. Hook: the number tracks the mental status, and the mental status is what you actually assess and document.
Strip 3 · Cardiac markers
| Value | Range | Rises | Peaks | Returns |
|---|---|---|---|---|
| Troponin I | below 0.04 ng/mL | 2–4 h | 10–24 h | 10–14 days |
| CK-MB | 0–5 ng/mL | 4–6 h | 18–24 h | 48–72 h |
| Myoglobin | 25–72 ng/mL | 1–3 h | 6–12 h | 24 h |
| B-type natriuretic peptide | below 100 pg/mL | with volume overload |
Hook: troponin is the one that stays up, so it answers the patient who waited two days before coming in. Assay cutoffs differ between laboratories.
Strip 4 · Thyroid
TSH 0.4–4.0 microunits/mL; free T4 0.8–1.8 ng/dL. Hook: TSH moves opposite the gland, which is why it reads backward.
Strip 5 · Lipids
Total cholesterol below 200 mg/dL; LDL below 100 mg/dL; HDL above 40 mg/dL in men and above 50 mg/dL in women; triglycerides below 150 mg/dL.
Strip 6 · Therapeutic drug levels
| Drug | Therapeutic level |
|---|---|
| Digoxin | 0.5–2.0 ng/mL |
| Lithium | 0.6–1.2 mEq/L, toxic above 1.5 mEq/L |
| Phenytoin | 10–20 mcg/mL |
| Vancomycin trough | 10–20 mcg/mL |
| Theophylline | 10–20 mcg/mL |
Hook: the level is read against the potassium and the kidney, not alone. A therapeutic digoxin level in a hypokalemic patient still behaves like toxicity.
Strip 7 · Urinalysis
Specific gravity 1.005–1.030; pH 4.6–8.0; protein, glucose, ketones, nitrites, and leukocyte esterase all negative. Hook: specific gravity is a volume number wearing a urine label.
Margin notethe marker that stays up is the one that tells the story.
Watch outa lithium level above 1.5 mEq/L is a hold-and-call, not a recheck-tomorrow.
→ BOOK 08 · P4 for acute coronary syndrome. → BOOK 11 · P6 for hepatic failure. → BOOK 10 · P9 for thyroid disease. → BOOK 05 · P7 for these drugs as drugs.
Takeawayeach panel answers one question about one organ, and the cardiac markers additionally answer when.
Reference ranges vary between institutions and reference laboratories. Follow local protocol.